a stimulant coming from the roots of the host. Table 13. Sorghum pedigrees found
completely free of damage by earhead bugs in two tests in. 1978-79. Pedigree.
Published by International Crops Research Institute for the Semi-Arid Tropics I C R I S A T Patancheru P.O. Andhra Pradesh 502 324, India
The International Crops Research Institute for the Semi-Arid Tropics ( I C R I S A T ) is a nonprofit scientific educational institute receiving support from a variety of donors, governments, and foundations. A l l responsibility for the information in this publication rests with I C R I S A T . Where trade names are used this does not constitute endorsement of or discrimination against any product by the Institute. The correct citation for this report is I C R I S A T (International Crops Research Institute for the Semi-Arid Tropics). 1980. A n n u a l Report 1978-79. I n d i a : I C R I S A T , Patancheru, A . P . 502 324.
Printed at Thomson Press (India) Limited. Faridabad.
I C R I S A T ' s Objectives T o serve a s w o r l d center t o i m p r o v e the genetic p o t e n t i a l f o r grain yield and nutritional quality of sorghum, pearl millet, pigeonpea, chickpea, and groundnut. T o develop f a r m i n g systems w h i c h w i l l help t o increase a n d stabilize
agricultural
natural and human
production
through
better
use
of
resources in the seasonally d r y semi-
arid tropics. To
identify
socioeconomic
and
other constraints
to
agri-
cultural development in the semi-arid tropics and to evaluate alternative means of alleviating them through technological a n d institutional changes. T o assist n a t i o n a l a n d r e g i o n a l r e s e a r c h p r o g r a m s t h r o u g h cooperation sponsoring
and
support
conferences,
and
to
operating
contribute
further
international
p r o g r a m s , a n d assisting extension activities.
by
training
About This Report
T h i s sixth A n n u a l R e p o r t covers research b y I C R I S A T f o r the c r o p
year beginning 1 June 1978 a n d e n d i n g 31 M a y 1979. It includes w o r k done a t I C R I S A T Center near H y d e r a b a d , I n d i a , a t substations o n the campuses o f a g r i c u l t u r a l universities i n f o u r different c l i m a t i c regions of I n d i a , a n d at n a t i o n a l a n d i n t e r n a t i o n a l research facilities i n the nine countries o f A f r i c a , L a t i n A m e r i c a , a n d the M i d d l e East where I C R I S A T scientists are posted. D e t a i l e d r e p o r t i n g o f the extensive activities o f I C R I S A T ' s m a n y research s u p p o r t units is b e y o n d the scope of this v o l u m e , b u t a comprehensive coverage of I C R I S A T ' s core research p r o g r a m s is i n c l u d e d . F o r easier management of m a t e r i a l , the year's activities are, i n general, reported u n i t b y u n i t u n d e r i n d i v i d u a l research p r o g r a m s ; however, i t s h o u l d b e b o r n e i n m i n d t h a t m o s t research a t . I C R I S A T i s h i g h l y i n t e r d i s c i p l i n a r y a n d the scientists w o r k i n teams. T h e i r w o r k is reported in more detail in individual program publications, which usually are available f r o m the p a r t i c u l a r research p r o g r a m .
Contents
I C R I S A T Governing Board I C R I S A T Personnel
vii ix
I C R I S A T Center's Research Environment
xiii
Acronyms and Abbreviations
xiv
Director's Introduction
1
T h e Cereals Sorghum Breeding Biochemistry Physiology Entomology Pathology Microbiology Looking Ahead Publications
Pearl Millet Breeding Biochemistry Physiology Entomology Pathology Microbiology Looking Ahead Publications
7 9 28 31 34 38 45 46 48 51 53 63 66 71 71 79 81 82
The Pulses Pigeonpea Breeding Biochemistry Physiology
85 87 93 95
Entomology Pathology Microbiology Looking Ahead Publications
Chickpea Breeding Biochemistry Physiology Entomology Pathology Microbiology Looking Ahead Publications
98 103 105 108 110 113 115 120 124 126 129 133 136 137
Oilseed Groundnut
141
Breeding Cytogenetics Physiology Entomology Pathology Microbiology L o o k i n g Ahead Publications
143 145 149 149 152 156 159 160
F a r m i n g Systems
163
RESEARCH IN SUBPROGRAMS Agroclimatology Environmental Physics Soil Fertility and Chemistry Land and Water Management Farm Power and Equipment Cropping Systems Agronomy and Weed Science
165 165 172 185 187 191 196 213
RESOURCE U T I L I Z A T I O N RESEARCH O N WATERSHEDS
219
C O L L A B O R A T I V E S T U D I E S 221 LOOKING AHEAD
224
PUBLICATIONS
227
Economics P r o g r a m
231
Agricultural Development in the Indian SAT Market Channels of I C R I S A T Crops in India Economic Assessment of Prospective Soil-, water-, and Crop Management Technologies for S A T India Model to Predict and Evaluate Runoff Economics of Improved Bullock-drawn Tool Carriers Field Studies of Watershed Development and Group Action Labor Availability and Allocation Factor Proportions and Technology Development Intercropping Socioeconomics Workshop L o o k i n g Ahead Publications
233 234
234 236 236 238 238 240 .241 241 241 242
Genetic Resources Unit
245
Sorghum Germplasm Pearl Millet Germplasm Pigeonpea Germplasm Chickpea Germplasm Groundnut Germplasm M i n o r Millets Germplasm Germplasm Distribution L o o k i n g Ahead Publications
252 252 254 255 255 256 256 256 257
International Cooperation West African Cooperative Program East African Cooperative Program Asian Cooperative Programs Cooperation with C I M M Y T Cooperation with I C A R D A Cooperation with Other Organizations
FELLOWSHIPS AND TRAINING WORKSHOPS. CONFERENCES, AND SEMINARS
259 261 269 270 272 272 273 273
276
Plant Quarantine
279
Computer Services
285
Library and Documentation Services
287
ICRISAT Governing Board
Dr. C.F. Bentley (Chairman) 13103-66 Avenue Edmonton, Alberta Canada T 6 H 1Y6 D r . Ewert Aberg (until Dec 1978) Department of Plant Husbandry Agricultural College of Sweden S-75007 Uppsala 7 Sweden Dr. J.G. de Souza" Rua Urandi 25/401 20.000 R i o de Janeiro Brazil Dr. O.P. Gautam (as of A p r 1979) Director General, I C A R & Secretary to the Government of India Dept. of Agricultural Research & Education Krishi Bhavan New Delhi India Dr. Arne Hagberg(as of Jan 1979) The Swedish Seed Association S-26800 Svalov Sweden D r Iwao K o b o r i Department of Geography University of T o k y o Hongo7-3-l, Bunkyo-ku Tokyo Japan
Dr. Klaus Lampe Deutsche Gesellschaft fur Technische Zusammenarbeit G m b H D-6236 Eschbom 1 1 Dag-Hammarskjold-weg Postfach 5180 Federal Republic of Germany M r . A . R . Melville Spearpoint Cottage Kennington Ashford, Kent United K i n g d o m T N 2 4 9QP M r . I.J. Naidu Chief Secretary Government of Andhra Pradesh Hyderabad India M r . G . V . K . Rao (until M a r 1979) Secretary to the Government of India Ministry of Agriculture and Irrigation New Delhi India D r . D j i b r i l Sene Minister of Rural Development Government of Senegal Dakar Senegal D r . M.S. Swaminathan (Vice-Chairman) Secretary to the Government of India Dept. of Agriculture and Cooperation Ministry of Agriculture and Irrigation Krishi Bhavan New D e l h i India a. Deceased Feb 1979 b. Now retired from service c. Now Member, National Planning Commission
vii
D r . L . D . Swindale (Ex-officio member) Director, I C R I S A T I C R I S A T Patancheru P.O. A n d h r a Pradesh 502 324 India D r . D.W. T h o m e d 365 East T h i r d N o r t h Logan, U t a h 84321 USA Dr. D . L . Umali (until M a r 1979) Assistant Director General, and
d. Deceased Jan 1979
viii
Regional Representative for Asia and the Far East Food and Agriculture Organization of the U N Phra Atit Road Bangkok Thailand Dr. Guy J. Vallaeys Deputy Director General, I R A T 110 rue de l'Universite Paris 7 eme France
ICRISAT Personnel— 31 May 1979 Administration
L.D. Swindale, Director J.S. Kanwar, Associate Director, Research R.C. McGinnis, Associate Director, International Cooperation B.F. D i t t i a , Principal Administrator V. Balasubramanian, Executive Assistant to the Director S.K. Mukherjee, Personnel Manager (until A p r 1979) N.S.L. K u m a r , Personnel Manager (acting) (as of M a y 1979) O.P. Shori, Fiscal Manager A. Banerji, Assistant Manager (Fiscal) R. Vaidyanathan, Purchase and Stores Manager R. Seshadri, Assistant Manager (Purchase and Stores) R.G. Rao. Records Manager S.K. Das Gupta, Scientific Liaison Officer A. Lakshminarayana, Scientific Liaison Officer (Jr) S.B.C.M. Rao, Travel Officer Col. P.W. Curtis, Security Officer R. Narsing Reddy, Transport Officer N. Rajamani, Liaison Officer, New Delhi Office
Crop Improvement Cereals J.C. Davies, Principal Entomologist, and Leader L.R. House, Principal Plant Breeder (Sorghum) D.J. Andrews, Principal Plant Breeder (Millets) A r a n Patanothai, Principal Plant Breeder (Millets) (as of Oct 1978) F.R. Bidinger, Principal Physiologist R.J. Williams, Principal Pathologist Claude Charreau, Project Leader, West Africa Project, Senegal A. Lambert, Principal Plant Breeder, Senegal
R.T. Gahukar, Principal Entomologist, Senegal C M . Pattanayak, Principal Plant Breeder (Sorghum), and Team Leader, Upper Volta P.K. Lawrence, Principal Plant Breeder (Millets), Upper Volta W . A . Stoop, Principal Agronomist, Upper Volta J.A. F r o w d , Principal Plant Pathologist, Upper Volta Ph. J. van Staveren, Assistant Agronomist, Upper Volta J.F. Scheuring, Principal Plant Breeder (Sorghum and Millets), M a l i (as of Jan 1979) S.A. Clarke, Field Trials Officer, M a l i (until July 1978) P.J. Serafini, Field Trials Officer, M a l i B.B. Singh, Principal Plant Breeder (Millets), Niger S.O. Okiror, Principal Plant Breeder, Nigeria N.V. Sundaram, Principal Plant Pathologist, Nigeria Gebisa Ejeta, Principal Plant Breeder (Sorghum), Sudan (as of A p r 1979) R.P. Jain, Principal Plant Breeder (Millets), Sudan Vartan Guiragossian, Principal Plant Breeder (Sorghum), Mexico S.Z. M u k u r u , Principal Plant Breeder (Sorghum and Millets), Tanzania K.V. Ramaiah, Principal Plant Breeder (Striga), Upper Volta Bholanath Varma, Plant Breeder (Sorghum) D.S. M u r t h y , Plant Breeder (Sorghum) B.L. Agrawal, Plant Breeder (Sorghum) B.V.S. Reddy, Plant Breeder (Sorghum) S.C. Gupta, Plant Breeder (Millets) K. Anand K u m a r , Plant Breeder (Millets) B.S. Talukdar, Plant Breeder (Millets) K . N . Rai, Plant Breeder (Millets) N. Seetharama, Plant Physiologist G. Alagarswamy, Plant Physiologist
ix
R.K. M a i t i , Plant Physiologist K . N . Rao, Plant Pathologist S.D. Singh, Plant Pathologist R.P. Thakur, Plant Pathologist S.R.S. Dange, Plant Pathologist K.V. Seshu Reddy, Entomologist R.V. Subba Rao, Microbiologist S.P. W a n i , Microbiologist V. Mahalakshmi, Post-doctoral Research Fellow (as of Jan 1979) S. Krishnan, Executive Assistant
Pulses J. M. Green, Principal Plant Breeder (Pigeonpea), and Leader K.B. Singh, Principal Plant Breeder (Chickpea), Alleppo, Syria W. Reed, Principal Entomologist Y . L . Nene, Principal Pathologist P.J. Dart, Principal Microbiologist D. Sharma, Sr. Plant Breeder (Pigeonpea) I.V. Subba Rao, Pulse Physiologist (until June 1978) K.C. Jain, Plant Breeder (Chickpea) Onkar Singh, Plant Breeder (Chickpea) C.L.L. G o w d a , Plant Breeder (Chickpea) S.C. Sethi, Plant Breeder (Chickpea) Jagdish K u m a r , Plant Breeder (Chickpea) K.B. Saxena, Plant Breeder (Pigeonpea) L.J. Reddy, Plant Breeder (Pigeonpea) S.C. G u p t a , Plant Breeder (Pigeonpea) N.P. Saxena, Plant Physiologist S.S. Lateef, Entomologist S. Sithanantham, Entomologist M . V . Reddy, Plant Pathologist M.P. Haware, Plant Pathologist J. Kannaiyan, Plant Pathologist O.P. Rupela, Microbiologist A . N . M u r t h i , Botanist (until A u g 1978) J . V . D . K . K u m a r Rao, Microbiologist Satish R a i , Post-doctoral Research Fellow (as o f A p r 1979) G . K . Bhatia, Post-doctoral Research Fellow (as o f M a y 1979) I. Madhusudhan Rao, Post-doctoral Research Fellow (as of A p r 1979)
x
Groundnuts R.W. Gibbons, Principal Plant Breeder, and Leader W.C. Gregory, Consultant J.P. Moss, Principal Cytogeneticist Duncan M c D o n a l d , Plant Pathologist (as o f A u g 1978) K. Maeda, Visiting Scientist, Plant Physiology N. Iizuka, Visiting Scientist, Virology D.V.R. Reddy, Sr. Plant Pathologist (Virology) S.N. Nigam, Plant Breeder A . M . Ghanekar, Plant Pathologist P. Subramanyam, Plant Pathologist V . K . Mehan, Plant Pathologist (as of Dec 1978) P.T.C. Nambiar, Microbiologist P.W. A m i n , Entomologist A . K . Singh, Cytogeneticist
Farming Systems B.A. Krantz, Principal Agronomist, and Leader J. Kampen, Principal Agricultural Engineer (Soil and Water Management) S.M. V i r m a n i , Principal Agroclimatologist R.W. Willey, Principal Agronomist L.P.A. Oyen, Assistant Agronomist (until A u g 1978) G.E. Thierstein, Principal Agricultural Engineer (Small Implements Development) M.C. K l a i j , Assistant Agricultural Engineer (Small Implements Development) F.P. Huibers, Assistant Agricultural Engineer (Soil and Water Management) M.B. Russell, Consultant, Soil Physics J.R. Burford, Principal Soil Chemist (as o f Oct 1978) S.V.R. Shetty, Agronomist Piara Singh, Soil Scientist Sardar Singh, Soil Scientist T.J. Rego, Soil Scientist K . L . Sahrawat, Soil Scientist M . V . K . Shiv K u m a r , Agroclimatologist A . K . Samsul H u d a , Agroclimatologist (as o f A u g 1978) S.J. Reddy, Agroclimatologist M.R. Rao, Agronomist
M.S. Reddy, Agronomist M. Natarajan, Agronomist V.S. Bhatnagar, Entomologist R.C. Sachan, Agricultural Engineer P. Pathak, Agricultural Engineer J. H a r i Krishna, Agricultural Engineer P.N. Sharma, Agricultural Engineer K . L . Srivastava, Agricultural Engineer (as o f A u g 1978) Harbans L a l , Agricultural Engineer R.K. Bansal, Agricultural Engineer O.P. Singhal, Agricultural Engineer Kabal Singh G i l l , Post-doctoral Research Fellow S.K.. Sharma, Sr.Research Technician Siloo Nakra, Administrative Assistant
D.L. Oswalt, Principal Training Officer A.S. M u r t h y , Sr. Training Officer B. Diwakar, Training Officer T. Nagur, Training Officer
Economics
Information Services
J.G. Ryan, Principal Economist, and Leader M. von Oppen, Principal Economist H.P. Binswanger, Principal Economist V.S. Doherty, Principal Social Anthropologist N.S. Jodha, Senior Economist D. Jha, Sr. Visiting Economist (as of July 1978) V.T. Raju, Economist S.L. Bapna, Economist B.C. Barah, Economist R.D. Ghodake, Economist R.S. Aiyer, Administrative Assistant
H.L. Thompson, Head (as of Nov 1978) G . D . Bengtson, Research Editor T.A. Krishnamurthi. Administrative Assistant S.M. Sinha, Senior Artist and Printshop Supervisor K.S. Mathew, Editor/Writer (as of Sept 1978) D.R. Mohan Raj, Editor/Writer (as of Dec 1978) H.S. Duggal, Head Photographer
Biochemistry R. Jambunathan, Principal Biochemist Umaid Singh, Biochemist V. Subrahmaniam, Biochemist
R.P.S. Pundir, Botanist P. Remanandan, Botanist (as of A u g 1978) V.R. Rao, Botanist
Plant Quarantine K . K . N i r u l a , Plant Quarantine Officer
Fellowships and Training
Statistics and Computer Services J.W. Estes, Principal Computer Services Officer J.A. Warren, Consultant S.M. Luthra, Computer Services Officer
Library and Documentation Services
Genetic Resources M . H . Mengesha, Principal Germplasm Botanist, and Leader (as of July 1978) L. J.G. van der Maesen, Principal Germplasm Botanist K.E. Prasada Rao, Botanist S. Appa Rao, Botanist
P.S. Jadhav, Librarian (acting until Feb 1979) Rama T i r t h , Librarian (as of M a r 1979)
Housing and Food Services A . G . Fagot, Manager
xi
G.B. G a i n d , Assistant Manager (Food Services) (as o f A p r 1979) H.S. Ratnagar, Administrative Assistant K . C . Saxena, Administrative Assistant
A . E . Jaikumar, Architect B.K. Sharma, Senior Engineer S.K.V.K. Chari, Electronics Engineer V. Lakshmanan, Executive Assistant P.M. Menon, Executive Assistant
Physical Plant Services E.W. N u n n , Station Manager N . N . Shah, Project Manager (until Oct 1978) F.J. Bonhage, Construction Supervising Officer Sudhir Rakhra, Chief Engineer (Civil) D. Subramanyam, Chief Engineer (Electrical) B.H. Alurkar, Senior Engineer Manmohan Singh, Senior Engineer S.K. T u l i , Senior Engineer T.J. Choksi, Senior Engineer J.K. Majumdar, Senior Engineer (until Dec 1978) S.S. Jangi, Engineer (until Jan 1979) S.K. Samy, Engineer D.V. Subba Rao, Engineer A . R . Das Gupta, Engineer (as of N o v 1978)
xii
Farm Development and Operations D.S. Bisht, Farm Manager (acting) S.N. Kapoor, Chief Engineer (Farm Operations) D . N . Sharma, Senior Engineer S.K. Pal, Plant Protection Officer K. Santhanam, Executive Assistant
International Interns Tetsuo Matsumoto, Microbiology L.K. Fussel, Cereal Physiology N.J. Neville, Groundnut Pathology
I C R I S A T Center's Research Environment M o s t o f the research r e p o r t e d i n this v o l u m e was carried o u t a t I C R I S A T Center, the I n s t i t u t e ' s m a i n research f a c i l i t y i n south-central I n d i a , w i t h i m p o r t a n t c o n t r i b u t i o n s made b y I C R I S A T scientists posted a t substations i n I n d i a , a n d i n A f r i c a , M e x i c o , a n d Syria. I C R I S A T Center is located on 1394 hectares near the village of P a t a n c h e r u , 2 5 k m n o r t h w e s t o f H y d e r a b a d o n the B o m b a y H i g h w a y . T h e e x p e r i m e n t a l f a r m includes t w o m a j o r soil types f o u n d i n the semia r i d t r o p i c s : Alfisols (red soils), w h i c h are l i g h t a n d d r o u g h t y , a n d Vertisols (black soils), w h i c h have a great w a t e r - h o l d i n g capacity. T h e a v a i l a b i l i t y o f these t w o soil types provides a n o p p o r t u n i t y t o c o n d u c t selection w o r k u n d e r c o n d i t i o n s representative o f m a n y areas o f the SAT. Three distinct a g r i c u l t u r a l seasons characterize the H y d e r a b a d area. T h e rainy season, also k n o w n as m o n s o o n or kharif, usually begins in June a n d runs i n t o September; m o r e t h a n 8 0 % o f the 8 0 0 - m m average a n n u a l r a i n f a l l occurs d u r i n g these m o n t h s . T h e p o s t r a i n y w i n t e r season o f O c t o b e r t h r o u g h J a n u a r y , also k n o w n a s p o s t m o n s o o n o r rabi, is d r y a n d c o o l a n d days are short. T h e s u m m e r season, h o t a n d d r y w i t h d a i l y temperatures between 3 6 a n d 4 3 ° C , i s f r o m F e b r u a r y u n t i l the rains begin again in June. These seasonal v a r i a t i o n s affect differently the g r o w i n g of the different crops. Cereal c r o p s g r o w n d u r i n g the p o s t r a i n y season rely on residual soil m o i s t u r e o r o n i r r i g a t i o n . I n the h o t d r y s u m m e r season, temperatures at f l o w e r i n g t i m e are very h i g h ; short-season crops m a y b e g r o w n i f i r r i g a t i o n i s p r o v i d e d . Chickpeas are p l a n t e d i n O c t o b e r o r N o v e m b e r a n d g r o w n o n residual soil m o i s t u r e ; o n l y one generation per year is g r o w n . June a n d J u l y are the m o n t h s in w h i c h pigeonpeas are p l a n t e d ; they g r o w t h r o u g h o u t the season a n d o n i n t o the p o s t r a i n y season w i t h o u t i r r i g a t i o n . A n a d d i t i o n a l generation o f e a r l y - m a t u r i n g types i s p l a n t e d a t I C R I S A T Center i n December a n d g r o w n w i t h i r r i g a t i o n so as to p r o v i d e a d d i t i o n a l genetic m a t e r i a l f o r the breeding p r o g r a m . T h e soil a n d c l i m a t i c c o n d i t i o n s are ideal f o r the g r o u n d n u t research applicable t o S A T a g r i c u l t u r e . I n a d d i t i o n t o the m a j o r effort u n d e r r a i n f e d c o n d i t i o n s i n the n o r m a l g r o w i n g season, i r r i g a t e d g r o u n d n u t crops are p r o d u c e d d u r i n g the p o s t r a i n y a n d h o t d r y s u m m e r seasons to facilitate progress in the breeding p r o g r a m .
xiii
Acronyms and Abbreviations Used in this Annual Report: AICMIP AICPIP AICRPDA
AICSIP
ALAD APAU AW
AWF CMMV CNRA
COPR CRISP CSIRO
DAS D E C PDP
DM EAAFRO
FAO
FESR
xiv
A l l India Coordinated Millet Improvement Project A l l India Coordinated Pulse Improvement Project A l l India Coordinated Research Project for Dryland Agriculture A l l India Coordinated Sorghum Improvement Project A r i d Land Agricultural Development Program Andhra Pradesh Agricultural University Autorite des Amenagements des Vallees des Volta (Authority for the Development of the Volta Valleys) available water fraction cowpea mild mottle virus Centre National de Recherche Agronomique (National Agricultural Research Center) Center for Overseas Pest Research Crop Research Integrated Statistical Package Commonwealth Scientific and Industrial Research Organization days after sowing Digital Equipment Corporation Programmable Data Processor downy mildew East African Agriculture and Forestry Research Organization Food and Agriculture Organization of the United Nations Federal Experimental Research Station, Puerto Rico
GAM
HYV IBPGR ICAR ICARDA
IDMRS IDRC IITA IPMAT 1PMDMN IPMEN IPMSN IRAT
IRRI ISGMN ISCRN ISPYT ISRN LAI LER MTSLDR
Groupe d'A melioration des M i l s (Millet Improvement Group) high-yielding variety International Board for Plant Genetic Resources Indian Council of Agricultural Research International Centre for A g r i cultural Research in D r y Areas I C R I S A T Data Management and Retrieval System International Development Research Centre International Institute of Tropical Agriculture International Pearl Millet Adaptation Trial International Pearl Millet D o w n y Mildew Nursery International Pearl Millet Ergot Nursery Internationa] Pearl Millet Smut Nursery Institute de Recherches A g r o nomiques Tropicales et des Cultures Vivrieres (Institute for Tropical Crops Research) International Rice Research Institute International Sorghum G r a i n M o l d Nursery International Sorghum Charcoal R o t Nursery International Sorghum Preliminary Yield Trials International Striga Resistance Nursery leaf area index land equipment ratio Multilocation Testing of Sorghum Lines for Drought Resistance
OAU ORSTOM
PAR PEQIA PMHT PMST PreIPMDMN
Organization for African U n i t y Office de la Recherche Scientifique et Technique Outre-Mer (Overseas Scientific and Technical Research Office) Photosynthetically active radiation Postentry Quarantine Isolation Area Pearl Millet H y b r i d T r i a l Pearl Millet Synthetics T r i a l
SAFGRAD SAT SDM SMIC SEPON TSWV UNDP USAID
Pre-International Pearl Millet Downy Mildew Nursery
VLS
Semi-Arid F o o d G r a i n Research and Development semi-arid tropics sorghum downy mildew Sorghum and Millets Information Center Sorghum Elite Progeny Observation Nursery tomato spotted wilt virus United Nations Development Programme United States Agency for International Development Village-Level Studies
XV
Director's Introduction The Consultative Group on International Agricultural Research at its meeting in November 1978 approved the establishment of an ICRISAT core program in Africa. This will enable us to make a longterm commitment to research to find new and improved technologies for the countries and people in semi-arid tropical Africa. Current projections show that these countries will have enormous cereal deficits by 1990 if improved technologies are not evolved and implemented. ICRISATcan now help to do something about this real and urgent need.
ICRISAT has established a core program in Africa. This will enable us to make a long-term commitment to research to find new and improved technologies for the countries and people in semi-arid tropical regions there.
T h e m a i n b u i l d i n g p r o g r a m f o r I C R I S A T Center a t P a t a n c h e r u , near H y d e r a b a d , I n d i a , was c o m p l e t e d this year. I C R I S A T staff w h o have been housed i n 2 0 o r m o r e separate b u i l d i n g s a r o u n d H y d e r a b a d a n d Patancheru have n o w been b r o u g h t together i n o u r f i n e new b u i l d ings. T h a n k s are due t o the d o n o r s ; t o o u r architects, Messrs. D o s h i , S t e i n , a n d Associates, f o r t h e i r splendid d e s i g n ; a n d t o the eight c o n tractors w h o b u i l t the c o m p l e x . Better staff c o m m u n i c a t i o n leading t o m o r e effective a n d m o r e i n n o v a t i v e research w i l l result f r o m this c o n s o l i d a t i o n . W e even have o u r o w n post o f f i c e — I C R I S A T P a t a n c h e r u P.O., A n d h r a Pradesh, I n d i a 502 324. In r e c o g n i t i o n of the need to b r i n g greater research resources to bear o n o u r t w o m a j o r cereals, the Cereal I m p r o v e m e n t P r o g r a m i s being d i v i d e d i n t o separate S o r g h u m I m p r o v e m e n t a n d M i l l e t I m p r o v e m e n t P r o g r a m s . Each p r o g r a m w i l l b e p r o v i d e d w i t h the f u l l c o m p l e m e n t o f scientific a n d s u p p o r t personnel, except t h a t the M i c r o b i o l o g y subp r o g r a m located i n M i l l e t I m p r o v e m e n t w i l l also w o r k o n s o r g h u m , a n d the E n t o m o l o g y s u b p r o g r a m located i n S o r g h u m I m p r o v e m e n t w i l l also w o r k o n millets. T h e various activities f o r the c o l l e c t i o n , maintenance, d e s c r i p t i o n , a n d d i s t r i b u t i o n o f the g e r m p l a s m o f o u r m a n d a t e crops have been consolidated i n t o a single Genetic Resources U n i t , w h i c h w i l l also operate new l o n g - t e r m g e r m p l a s m storage facilities w h e n they are completed. A d v a n c e d breeding m a t e r i a l f o r p e a r l m i l l e t continues t o lead the w a y i n o u r c r o p i m p r o v e m e n t w o r k . Some o f the m a t e r i a l f i r s t entered i n t o the A l l I n d i a m i l l e t i m p r o v e m e n t trials 3 years ago is n o w reachi n g the stage of f o u n d a t i o n seed increase. V i r t u a l l y a l l the m a t e r i a l released b y I C R I S A T i s m o d e r a t e l y o r h i g h l y resistant t o d o w n y m i l d e w , the m o s t prevalent m a j o r disease of this c r o p . Male-sterile lines o f pigeonpea t h a t c a n b e used i n the p r o d u c t i o n o f h i g h - y i e l d h y b r i d s represent a n i m p o r t a n t b r e a k t h r o u g h f o r this g r a i n legume c r o p a n d are e x c i t i n g the interest of pigeonpea breeders in n a t i o n a l p r o g r a m s . G o o d progress i s also being made o n o u r o t h e r three m a n d a t e c r o p s , a n d s o r g h u m selections made b y I C R I S A T p l a n t breeders are being m u l t i p l i e d f o r f a r m e r use i n M a l i a n d U p p e r V o l t a . T h e n e w f a r m i n g systems package f o r rainy-season c r o p p i n g o f deep Vertisols has p r o v e d successful f o r a seventh year of e x p e r i m e n t a t i o n a t I C R I S A T . T h e package w i l l n o w b e tested o n f a r m e r s ' f i e l d s i n three o f t h e six villages i n I n d i a where o u r economists have been l i v i n g f o r
2
The main building program for ICRISA T Center at Patancheru, near Hyderabad, India, was completed this year. Above is the administration building.
the past 3 years. In this first year of on-farm experimentation we tested crop combinations proposed by the farmers themselves and by the cooperating scientists in the local agricultural universities. Use of the ICRISAT package of practices on small watersheds will commence next year, taking account of these preliminary results. Improvement of our research facilities continues. An additional 140 ha of arable land was developed and brought under cultivation at ICRISAT Center during the year, increasing the total cultivated area of the research farm to 725 ha. Drainage in the precision fields was improved, and the irrigation facility was extended from 200 ha to 300 ha in research areas demanding moisture control. Land improvements were also completed at two of our Indian substations, Hissar and Bhavanisagar. We held workshops and conferences this year to improve our communications with scientists in participating countries and to sort out new directions for ICRISAT research. They included such subjects as intercropping, agroclimatology, the diseases of sorghum, and soilborne diseases of chickpea.
3
A workshop on socioeconomic constraints was held to determine the nature of our future program in Africa. It was preceded by two detailed, comprehensive surveys of the literature on production and marketing economics in Sahelian countries, conducted by Dr. David Norman of the Kansas State University and Dr. Barbara Harriss of the University of East Anglia. These social scientists were unanimous in their view that new technology, not just adapted technology, was essential to development in the Sahelian countries. A major event of the year was the in-depth review of ICRISAT conducted by a panel of nine experts headed by Dr. Lloyd T. Evans acting on behalf of the Technical Advisory Committee of the C G I A R . I am pleased to report that the panel was highly commendatory of ICRISAT and its work and understood full well the tremendous
A major event of the year was the in-depth Quinquennial Review of ICRISAT by a panel of nine international experts. Here panel members review the progress made in developing new pearl millet male-sterile lines.
4
challenge w e face i n f u l f i l l i n g o u r m a n d a t e t o w a r d s i m p r o v i n g the health, w e a l t h , a n d w a y o f life o f the people o f the semi-arid tropics. Finally, I w o u l d like to record my thanks to our many collaborators a n d c o o p e r a t o r s i n I n d i a , i n A f r i c a , a n d o t h e r areas o f t h e S A T a n d the developed w o r l d . Especially appreciated is the c o n t i n u i n g strong c o m m i t m e n t a n d s u p p o r t received f r o m the G o v e r n m e n t s o f I n d i a a n d U p p e r V o l t a a n d the State G o v e r n m e n t o f A n d h r a Pradesh, I n d i a . W i t h o u t their aid I C R I S A T could not f l o u r i s h .
5
6
Breeding Population Breeding International Sorghum Preliminary Yield Trials (ISPYT) ISPYT-1 ISPYT-2 S 2 Progeny Evaluation Trials Breeding for Postrainy-Season Sorghum Types Grain Quality Sorghum Elite Progeny Observation Nursery (SEPON) Regional Tests Selection for Grain M o l d Resistance Selections in the field Breeding for Charcoal Rot Resistance Screening for Resistance to Charcoal Rot Breeding for Pest Resistance Shoot Fly Stem Borer Midge Earhead Bug Breeding for Striga Resistance Screening for Resistance to Striga Laboratory screening for low stimulant production Field testing of low stimulant lines Field testing for Striga resistance Breeding for Resistance to Drought F o o d Quality Evaluation of Chapati Quality Ugali Properties Uji
8
9 9 10 10 10 10 12 12 13 13 15 15 15 16 18 18 19 19 21 21 21 21 22 22 25 25 25 27 27
Chapati and Ugali Qualities Improvement for Lysine
27 27
Biochemistry
28
Physiology
31 31 31 32
Drought Resistance Charcoal Rot Resistance Resistance to Shoot Fly Seedling Drought Resistance Screening
Entomology Pest Incidence and "Carryover" Studies Sorghum Shoot Fly Stem Borer Other Pests Pest Nurseries
Pathology Grain M o l d Resistance Screening At I C R I S A T Center Field screening Laboratory screening Multilocational testing Charcoal Rot A t I C R I S A T Center Multilocational testing Leaf Blight and Rust International Sorghum Leaf Disease Nursery Downy Mildew
33 34 35 35 37 38 38 38 38 38 39 39 40 40 40 41 42 44 44
Microbiology
45
Looking Ahead
46
SORGHUM
Breeding Population Breeding To meet the long-term objective of providing improved breeding material to the national programs, a number of broad-based randommating sorghum populations have been developed. Testing of selected lines in International Sorghum Preliminary Yield Trials (1SPYT) has indicated that with improvements in the base population there is improvement in the lines extracted from them. However, some
high-yielding derivatives lack agronomically important traits. Therefore, a crossing program has been undertaken to improve these elite lines by pedigree methods of breeding. Another important extension of the population improvement program has been the incorporation of additional useful variability into random-mating populations. During the past few years several good sources of resistances to grain mold, shoot fly, Striga, and stem borer have been identified. These sources of resistances have been crossed to random-mating populations in order to enhance the opportunity of selection for these traits.
Potential varieties of sorghum from ICRISAT are seed increased for international distribution.
International Sorghum Preliminary Yield Trials (ISPYT)
The ISPYT are composed of the most-advancedgeneration elite lines derived from the random mating populations under recurrent selection at I C R I S A T Center. During 1978, the lines were grouped into two maturity types for separate trials: early types that flowered in less than 60 days at I C R I S A T Center were placed in I S P Y T - 1 , and medium to medium-late maturing types that flowered after 60 days from planting were tested in ISPYT-2. Each of these trials was distributed to 28 locations in the semiarid tropics. I S P Y T - 1 . This trial consisted of 30 early maturity lines. Data were returned from 17 locations, a substantially better return than that of the previous year, and more are expected f r o m locations where the crop is grown at a different time of the year. At the 12 locations where it was possible to make an analysis of variance for grain yield, the coefficient of variation (CV) ranged f r o m 14 to 46%, and was less than 20% at only six locations. The grain yield of some good entries is given in Table 1. Several lines produced higher grain yield than the local check at each location. Diallel Pop-7 was outstanding at Nazareth in Ethiopia and at Rahuri in I n d i a ; it averaged third in rank over 12 locations. Bulk-Y-398 ranked first at Hissar and Indore (India) and second at Dharwar (India) and Nazareth (Ethiopia). A nonrestorer line, US/B-292, performed better at almost all locations in Africa than in India. Similarly, Bulk-Y-138 was good in Africa. On the basis of the mean performance over locations, FLR-53—a line f r o m the Fast Lane-R population—gave highest grain yield, followed by SC-108, a check developed by Texas A & M . ISPYT-2. This trial consisted of 60 medium to medium-late maturity lines. Data were reported f r o m 20 of the 28 locations, but some locations d i d not report the grain yield. The analysis f o r
10
grain yield was performed on data f r o m 14 locations. The results f r o m trials with coefficients of variation of 35% or less are reported in Table 2. Indian Syn-235 gave the highest mean yield, followed by Bulk-Y-1253. The variety GG-1483 performed well in West Africa and ranked first in Upper Volta, M a l i , and Ghana.
S2 Progeny Evaluation Trials These trials were conducted for three random mating populations—US/R, US/B, and West African Early. This was the second cycle of S 2 testing for US/R and US/B populations and the first for the West African Early population. The tests included 195 S2 lines from each population, along with five checks. A l l trials were conducted at I C R I S A T Center, and at I C R I S A T regional substations at Bhavanisagar and Dharwar. In addition, the US/R trial was conducted at K o b o , Ethiopia; the US/B trial at I C R I S A T Cooperative Center in Sudan; and the West African Early trial in Upper Volta and Thailand. The mean grain yield in the US/R S 2 progenies ranged from 1819 to 6571 kg/ha, with an overall population mean of 4150 kg/ha; the best check, SC-108, yielded 3778 kg/ha. Based on overall performance of S 2 lines for grain yield and other agronomic traits, 30 S 2 lines, along with nine other lines selected as sources of resistance to pests and diseases, were recombined the following season to synthesize the population. Similarly, 31 lines were selected f r o m the US/B S 2 progeny evaluation trial for recombination along with ten good nonrestorer lines. The data on S 2 progenies of the West African Early population received f r o m the five test locations showed many lines at each location with significantly higher grain yield than the local check. The mean grain yield of the entire population at all five locations was 3142 kg/ha. Thirty-seven lines with a mean grain yield of 3429 kg/ha were selected for recombination, thus providing a selection differential of 287 kg/ha. Since this population has good adaptation in West Africa, selection of the lines was biased towards those performing well there.
11
Table 2. Grain yielda and rankb of promising lines of ISPYT-2 (1978). India
Pedigree Indian Syn-235 Bulk-Y-1253 GG-i482 Bulk-Y-1020 Indian Syn-250 Indian Syn-195
Indian Syn-422 SC-108 CSV-4 Local
CV(%) LSD at 5%
Dharwar
Bhavanisagar
Indore
Hissar
Sri c Lankac Thailand
Upper Voltac
Mali c
Ghanac 720 (5) 587 (21) 947 (1) 511 (33) 890 (2) 644 (17)
3343
170 (59) 303 (54) 303 (54)
2679
5970 (2) 7330 (1) 5386 (5) 4997 (13) 4744 (17) 3990 (38)
2950 (8) 2500 (22) 1938 (43) 2913 (9) 1725 (51) 1850 (46)
3781 (17) 4830 (5) 3472 (22) 5015 (3) 3410 (24) 4877 (4)
1683 (4) 1283 (17) 917 (35) 1783 (1) 1283 (15) 1583 (7)
2515 (16) 2560 (14) 2336 (26) 2560 (15) 1999 (41) 2358 (23)
4658 (8) 2763 (51) 3573 (30) 4118 (18) 5615 (2) 3316 (40)
4817 (3) 4633 (4) 5750 (1) 3208 (33) 3017 (37) 4375 (7)
2992 (14) 2898 (16) 4391
5192 (8) 4511 (23) 4705 (18) 4511 (22)
2400 (24) 3338 (5) 1875 (45) 3725 (1)
3472 (21) 2994 (38) 3318 (27) 6250 (1)
1750 (2) 1383 (12) 617 (47) ND
1752 (48) 2381 (22) 2785 (7) 3369 (1)
3205 (42) 3129 (43) 4870 (6) 3898 (23)
3900 (16) 3283 (30) 2192 (58) 3500 (22)
2273 (37) 3164 (8) 2266 (38) 3703 (4)
17.2 1410
31.2 1444
20.7 1362
27.0 1177
18.6 1361
19.2 1285
30.5 1515
35.0 375
(1) 2523 (23) 3836 (3) 2797 (17)
Mean
3265 3190 3070 2947 2866
2721 2548
a. Grain yield (kg/ha) based on a plot size ranging from 3.6 to 7.5 sq. m at different locations and two replications. b. Figures in parentheses indicate ranking. c. Station locations arc as follows: Sri Lanka—ARS, Mahailluppallama; Thailand—Khonkaen; Upper Volta—Kamboinse; Mali—Cinzana; Ghana—Nyankpala. N D = N o data.
Breeding for Postrainy-Season Sorghum Types T w o trials conducted during the 1978 postrainy season consisted of entries that looked promising in the breeding nursery of population lines during the 1977 postrainy season. The crop ripened in moisture-stress conditions, and there was severe lodging due to charcoal rot. Also, there was heavy infestation of rust quite early in the growing period. This gave an opportunity to screen against charcoal rot and rust and also to measure the yield. The promising lines with good yield and less susceptibility to charcoal rot and rust are
12
presented in Tables 3 and 4. Several lines in both trials yielded significantly more than the checks, Maldandi (local) and CSH-8 (a released hybrid from the A l l India Coordinated Sorghum Improvement Project).
Grain Quality Sorghum varieties that mature 2 to 5 weeks earlier than local ones are of great interest to breeders. Yields of early maturing varieties are usually better if the rainy season is shorter than expected. If the rains continue beyond expectation, the crop faces a severe problem of grain
molding. A search for food-quality sorghums with grain mold resistance has been under way at I C R I S A T for several years, and varieties with good levels of resistance to Curvularia and Fusarium molds have been identified. This material is now widely used in the SAT, while our research continues to seek yet higher levels of resistance to grain molds. Sorghum Elite Progeny Observation Nursery (SEPON) SEPON-1978, comprising 46 elite selections ( F 6 and F 7 generations) from adapted x moldresistant crosses, was dispatched to 21 cooperators in 15 SAT countries. The nursery was planted as a replicated yield trial in some locations only, while at others unreplicated observation plots were sown. Results on the overall performance were available from 18 locations in 12 countries, and 6 to 20 entries were selected by various cooperators. Table 5 presents the significantly better performers across locations out of Table 3. Grain yielda and rank of promising selections from sorghum Trial 1 conducted in the 1978 postrainy season.
Pedigree
Grain yield (kg/ha)
Rank
Indian Syn-387-1 2KX17 US/R-408-405 Bulk-Y-1047 GG-1483
2467 2458 2433 2308 2192
1 2 3 4 5
GG-1485 Diallel-12-875 Diallel-1008-771 Diallel-1008-778
2133 1917 1892 1850
6 8 9 12
CSH-8 Maldandi
1208 1017
30 34
CV(%) LSD at 5%
19 454
a. Grain yield (kg/ha) based on 6 sq m with four replications.
Table 4. Grain yield" and rank of the promising Uses from sorghum Trial 2 conducted in the 1978 postrainy season.
Pedigree
Grain yield (kg/ha)
Rank
Indian Syn-405-2 GG-1485 Diallel-1008-761 Indian Syn-395 Indian Syn-315
2633 2608 2567 2549 2549
I 2 3 4 5
Diallel-12-876 Tall Diallel-465-813 Diallel-1008-36 Indian Syn-385-3 CSH-8 Maldandi
2417 2333 2317 2233 1267 1400
7 9 10 11 69 61
CV (%) LSD at 5%
12 403
a. Grain yield (kg/ha) based on 6 sq m with two replications.
48 entries tested. A majority of the entries were relatively less susceptible to leaf diseases, although a few were highly susceptible to sooty stripe and anthracnose. Some of the entries did exceedingly well under low rainfall conditions in Botswana. In M a l i , Entry N o . 13 yielded 1300 kg/ha more than the local check. In Upper Volta, Entry Nos. 15 and 8 yielded much higher than the local check, while in Sudan, Entry N o . 42 produced the highest yield. Mean yields across locations indicate entries 15 and 17 as the best.
Regional Tests Yield trials comprising 145 F 6 and F 7 generation lines were conducted in the rainy season at I C R I S A T Center, Dharwar, and Bhavanisagar. In Dharwar there was a good opportunity to assess leaf rust incidence, while at Bhavanisagar grain mold damage, particularly by Phoma, was scored. Grain yield ranged from 3500 to 6500 kg/ha. On the basis of overall
13
14
performance, six entries were selected from these experiments for the A l l India Coordinated Sorghum Improvement Project Preliminary Yield Trials (1979). The grain yield performance and other attributes of the six entries, along with one hybrid and two varietal checks are listed in Table 6. Selection for Grain Mold Resistance Selections in the field. A total of 3140 F 3 , F 4 , F 5 , and F 6 progenies and 487 less susceptible checks from 1977 testing were screened for resistance to the two grain molds Curvularia and Fusarium in the rainy season in collaboration with the pathology unit. Plantings of these and susceptible checks were repeated frequently. A l l rows were evaluated for their reaction to Curvularia and Fusarium on a scale of 1 to 5. Relatively clean panicles (with a score of 3 or less) with good grain quality were selected. The results of selection are summarized in Table 7. Efforts to diversify the genetic origin and plant morphology of the breeding material were intensified. Using resistant sources for grain mold, charcoal rot, shoot fly, stem borer, and
interesting lines from the world collection with good grain quality, 1292 new crosses were made, of which 723 were single, 376 were double and three-way, and 193 were intercrosses. F1 generation material from 1756 crosses made in previous seasons was also grown. The mold-resistant composite was backcrossed for the third time with less mold-susceptible selections from the rainy season. In observation plots incorporating frequent checks, 1687 hybrids were evaluated. During the postrainy season, 922 hybrids with moldresistant seed parents were inoculated with charcoal rot, 69 were found to beless susceptible. Seed of selected hybrids was increased for replicated yield testing in India in 1979. Sixteen entries were found to be nonrestoring and eight are being developed into male-sterile seed parents for hybrids.
Breeding for Charcoal R o t Resistance The stalk rots, particularly charcoal rot, have caused severe grain losses in a number of
Table 6. Performance of some elite sorghum selections in India in the 1978 rainy season. Grain yield (kg/ha) b
Pedigree
Plant Days to heighta flowera (cm)
HyderBhavaniMean abad Dharwar sagar
Rust
Grain mold
Charcoal rot
Food qualityc
(SC-108-3 x 3541)-19-1 (SC-108-3 x E-35-1)-29-2 (SC-108-4-8 x 3541)-40-l (CS-3541 x IN-15-2)-26-l (SC-108-3 x 3541)-51-1 (SC-108-3 x 3541)-3-l
69 71 73 67 68 66
172 181 182 174 154 151
5 496 5405 4825 5463 3 896 5 348
5849 5877 5527 5333 4238 5817
5661 5455 5650 5026 4400 4557
5668 5579 5334 5274 4178 5240
2.0 2.5 2.0 2.0 2.0 2.0
2.5 2.0 2.5 2.5 2.5 3.0
3.0 2.5 2.0 2.5 2.5 3.0
1.0 1.5 2.0 1.5 2.5 2.0
CSV-3 (370) CSV-4(3541) CSH-6
70 73 64
176 141 167
4748 4131 6231
2601 4460 6576
4056 3125 4017
3801 3905 5608
4.5 2.0 3.0
5.0 3.0 3.0
4.0 3.0 4.0
5.0 3.0 2.0
a. Average across locations. b. Grain yield data is quoted f r o m replicated trials with plot size of 18.0,7.3, and 4.0 sq m in Hyderabad, Dharwar, and Bhavanisagar, respectively. Percent moisture of the grain from Hyderabad ranged f r o m 10.0 to 11.5. c. A l l characters were scored on a scale of 1 to 5 where, 1 = no molds, 2 = less than 10% grains moldy, 3 = 11 to 25% grains moldy. 4 = 26 to 40% grains moldy, and 5 = more than 40% grains moldy.
15
Table 7. Mold-resistant selections of sorghum obtained in the 1978 rainy season by screening 3627 F 3 , F 4 , F5, and F6 generation progenies (inoculated with Curvularia and Fusarium). Scorea Origin 1977 selections Single crosses Three-way crosses Segregating generations Single crosses Double crosses Three-way crosses Total
1.5
2.0
2.5
3.0
Total
11 0
44 4
2 0
0 0
57 4
10 5 42
29 2 86
4 1 8
2 0 4
45 8 140
68
165
15
6
254
a. Score. 1 = no molds. 2 = less than 10% grains moldy, 3 = 11 to 25% grains moldy, 4 = 26 to 40% grains moldy, and 5 = more than 40% grains moldy.
countries, including India, Ethiopia, Tanzania, Upper Volta, Mexico, Colombia, and Nicaragua. This disease, caused by Macrophomina phaseolina (Tassi) G o i d , is generally associated with high temperature and stress, particularly drought stress. Identification and development of source material is an important step in breeding for resistance to this disease. In cooperation with the pathology group, screening for resistance to charcoal rot began in the 1977-78 postrainy season. Screening for Resistance to Charcoal Rot The 28 lines selected from the 1977-78 postrainy season were organized into a nursery by our pathologists and screened at eight locations outside India and eight locations within India. Of these locations, the disease was most severe at Nandyal, Andhra Pradesh, India. Based on thedisease score at Nandyal, 11 parental lines were found least susceptible to the disease. Several breeding materials ( F 1 to F 5 ) were generated f r o m these parental lines (Table 8). These were screened using tooth-pick inoculation technique in the 1978-79 postrainy season at Hyderabad.
16
The initial screening in the 1978-79 postrainy season included different sets of materials with the aim of diversifying potentially promising source materials. The nature of the materials and the number of lines screened and selected are given in Table 9. Fifty-one selections were made. The 50 entries selected as less susceptible to the disease from the 1977 postrainy season initial screening were screened in the 1978 postrainy season at Hyderabad and Dharwar. At Dharwar, the disease spread was greater than at Hyderabad (1.19 mean number of nodes crossed vs 0.39 in the early flowering, 1.24 vs 0.59 in the medium flowering, and 1.49 vs 0.74 in the late flowering group). The correlations for the mean number of nodes to which the disease spread within the stems at Dharwar and at Hyderabad were not significant in all three maturity groups. The coefficients of variations for the mean number of nodes crossed were large (43 to 65%), suggesting substantial environmental effects at each location. This may be partly responsible for the low levels of correlations. Efforts to improve the screening technique and to better understand the environmental influence on the expression of charcoal rot are in progress.
Under moisture-stress conditions susceptible varieties were devastated by charcoal rot. A resistant variety (background)
was selected for use in our breeding program.
Table 8. Least susceptible parental lines and the number of various generations of sorghum breeding materials screened for charcoal rot at Hyderabad in the 1978-79 postrainy season. Number of Parental lines
F1s
F2s
F3s
F4s
(954063 x CS-3541)-30 (954068 x CS-3541)-ll (954068 x CS-3541)-64 SC-120-14 CS-3541
172 163 106 83 278
80 24 53
48 15 6
11
128
914
68
IS-121 IS-1235 4-22 8-55 20-87 21-78
79 137 120 7 184 6
13 37 13 3 88 5
1 2
Total
1335
444
F5s
Total
10
311 202 165 83 1398 93 176 133 10 300 11
28
1014
79
10
2882
17
Table 9. Natare and number of sorghum Hues screened and selected from the charcoal rot 1978 79 postrainy season screening nursery. No. of Entries Material
Tested
Selected
MTSLDR a -1979-Early —Medium " — Late Karper's Nursery
52 55 45 108
15 4 3 11
R-lines from B4 field 1978 rainy season Shoot fly-resistant lines Stem borer-resistant lines Bijapur material Rabi selections (germplasm)
52 12 21 45 53
0 1 0 0 7
58 79 76
10 0 0
59
0
715
51
Murty's classification (germplasm) Population derived B-lines Conventional B-lines B-lines from B4 field 1978 rainy season Total
.
a. MTSLDR-1979-Multilocation Testing of Sorghum Lines for Drought Resistance.
Breeding for Pest Resistance Shoot Fly (Atherigona soccata Road.) This year an effort was made to evolve a more effective and efficient screening technique for the shoot fly. A l l undamaged plants were identified within 4 weeks of emergence in order to avoid confusion among factors contributing to resistance. One of several mechanisms contributing to resistance to the shoot fly is oviposition nonpreference; it was found to be associated with the presence of trichomes (microscopic hairs) on the leaves. At times, eggs are laid even on trichomed lines, but few deadhearts are
18
formed. It appears that trichomes offer mechanical resistance by interfering with the migration of the maggot to the feeding point. Observations f o r oviposition nonpreference and the presence or absence of trichomes were made on undamaged plants to sort out escapes and to categorize the identified resistant material. Material identified in one of four categories (Table 10) shows that contribution of trichomes and antibiotic factors to shoot fly resistance was in equal proportion, indicating that antibiotic factors are also important. During the 1978 rainy season, 3223 undamaged plants were identified, but only 1089 agronomically superior ones were harvested. The number of escapes was less than 7%. D u r i n g the rainy season, 480 single crosses between resistant and agronomically elite lines were made, 109 single crosses were evaluated, and 26 agronomically superior crosses were selected. D u r i n g the 1978 postrainy season, 188 more single crosses were made. The 480 crosses made during the previous season were advanced, and 205 of the best crosses were selected. In the 1978 postrainy season, the harvest f r o m the 1978 rainy season was planted for retesting in the first week of January 1979. The shoot fly population at that time was low (about 70% damage on the susceptible checks). Several entries (mostly in F 6 , F 5 , and F 4 stage) were found to have more than 90% resistance with this pressure. Some entries identified as very good recovery lines had a high level of resistance. In cooperation with physiologists, observations were made on the expression of the "glossy t r a i t " (a light yellowish-green plant color and glossy leaf surface) in the seedling stage (see also Sorghum Physiology section). This trait was expressed more by trichomed lines than by nontrichomed ones (Table-11). Although the material was not bred to include this trait, it was frequently found in the more resistant lines. It was observed that shoot fly eggs were also laid on glossy plants, but fewer deadhearts resulted. If it proves to be a trait closely associated with shoot fly resistance it w i l l make the screening operation easier. Plans for a more
Table 10. Sorghum breeding: shoot fly selections based on the presence or absence of trichomes. Number of selections made during Trichomes
Egg laying
Category
1977 postrainy
1978 rainy
1. No 2. No 3. Yes
No Yes No
201 123 100
73 515 106
4. Yes
Yes
Escape Antibiosis Ovipositional nonpreference Mechanical
79
(39.8%) 40:60a
(6.69%) 50:50°
400
a. Proportion of trichomed and nontrichomed material (nos. 3 and 4 are trichomed; 2, not trichomed; 1, not considered).
detailed study of this trait are under way. (Preliminary observation indicates that the glossy trait also contributes to reduce infestation by the flea beetle and the shoot bug [Perigrinus maidis].) D u r i n g the summer season (March sowing) a set of 2247 primary resistant progenies was planted at Hissar. Shoot fly attack was severe; each plant had 15 to 20 eggs. In this nursery only 17 entries had less than 30% damage. M 3 5 - 1 , a resistant check, had 50% damage.
Stem Borer (Chilo partellus Swin.) The screening facilities for this pest were expanded substantially by the Cereal Entomology U n i t
during 1978-79. In the 1978 rainy season, 2.8 ha of breeding material were infested artificially with five to six larvae per plant. In the postrainy season, 2 ha of material were screened in the same way. Stem borer infestation was started 25 days after seedling emergence. Screening in the postrainy season proved more effective than in the rainy season (Table 12).
Midge (Contarinia sorghicola Coq.) A search in 1978-79 to identify suitable locations and seasons for testing breeding material against midge under natural conditions indicated Dharwar to be a promising location for screening in the rainy season. Plantings were
Table 11. Sorghum breeding: shoot fly breeding material showing the glossy trait
Type of material
Number of entries showing trait
Trichomed Nontrichomed Very good and good recovery resistant lines Recovery lines
266 (328) 329 (483) 180 (309) 679 (1330)
Percent 81.09 68.11 58.25 51.00
Figures in parentheses indicate the number of entries grown.
19
20
delayed until the first week of August, and the incidence of midge was severe. At maturity, 412 separate promising plant selections were made for midge and some were common selections for both midge and Calocorus.
Earhead Bug (Calocoris angustatus Leth.) During the 1978 rainy season, a substantial nursery of segregating material for midge resistance was planted 6 weeks later than normal sowing in hopes of a high midge population, which did not develop. However, during the grain-filling stage, this material was heavily attacked by earhead bugs. At harvesting time, 370 heads completely free of damage (though earhead bugs were present in these heads) were selected from a nursery of 3 ha. In order to confirm resistance, these selections were planted in separate progeny plots and artificially infested in the next season (1978 postrainy). Excellent grain quality and bug resistance was found in 36 entries, which are now in the F 5 and F 6 stage. This material will be further tested for midge reaction during the 1979 rainy season at Dharwar. There appears to be a good possibility of finding some lines with resistance to both midge and earhead bugs. The pedigree details of these lines are given in Table 13.
Breeding for Striga Resistance Striga is a parasite of sorghum, maize, sugarcane, millets, and several grasses w i t h a potential to cause severe damage to the host crop. Striga hermonthica in A f r i c a ; and S. asiatica in India, parts of S.E. Asia, Africa, and N o r t h Carolina (USA) are of significant economic importance.
Screening for Resistance to Striga Laboratory screening for low stimulant production. It is generally understood that seeds of Striga w i l l germinate only in the presence of a stimulant coming f r o m the roots of the host
Table 13. Sorghum pedigrees found completely free of damage by earhead bugs in two tests in 1978-79. Pedigree (IS-3574C x SC-108-4-8)-11-4 (IS-12612C x PHYR)-4-l-4 (IS-12573C x 2219B)-4-2-l (IS-12573C x 2219B)-19-2-l (1S-12573C x PHYR)-2-l-l (1S-12573C (IS-12573C (IS-12573C (IS-12573C (IS-12573C
x x x x x
PHYR)-2-2-1 PHYR)-2-2-2 SC-108)-2-2-3 SC-108-3)-4-3-1 SC-108-3)-4-4-2
(IS-12573C (1S-12573C (IS-12573C (1S-12573C (IS-12573C
x x x x x
SC-108-3)-7-3-l SC-108-3)-18-l-l SC-108-3)-18-2-3 SC-108-3)-18-3-1 SC-108-3)-18-3-2
(IS-12573C (IS-12573C (IS-12573C (IS-12573C (IS-12573C
x SC-108-3)-18-5-3 x SC-108-3)-19-l-l x SC-108-3)-19-l-2 x SC-108-3)-19-l-3 x SC-108-3)-19-l-5
(IS-12573C (IS-12573C (IS-12573C (IS-12573C (IS-12573C
x x x x x
SC-108-3)-19-2-l SC-108-3)-19-2-2 SC-108-3)-19-2-4 SC-108-3)-19-2-5 SC-108-3)-19-2-6
(2KX6 x IS-12573C)-32-1-1 (EC-64734 x IS-2579C)-29-l-l (EC-64734 x IS-2579C)-42-l-l (A-30 x IS-12573C)-16-1-1 (A-30 x S-Girl-MR-l)-7-l-l (Diallel (C1)-465-2-S8) x IS-2579C)-2-l-l (Bulk-Y-S6-55-2 x IS-2816C)-36-1-1 (Bulk-Y-S6-55-2 x IS-2816C)-68-1-1 (Bulk-Y-S6-55-2 x IS-12573C)-1-1-1 (Bulk-Y-S6-55-2 x IS-12573C)-12-1 (IS-1082 x IS-2816C) x FLR-101-5-6-1 plant. In the year under report, 4750 sorghum lines were screened for stimulant production.
21
They belong to various taxonomic groups {Table 14). Of the total, 370 were found to produce stimulant less than 10% of the control. Altogether, mote than 13 000 getmplasm entries have been screened and 730 lines have been identified as low stimulant producers in the past few years.
correlation was low, reducing the value of laboratory screening for low stimulant production as the practical tool previously anticipated for breeding against Striga. However, since the correlation was positive and significant, there is a need to refine the laboratory screening technique.
Field testing of tow stimulant lines. The laboratory technique of screening for low stimulant production has limited practical value as a selection tool unless it correlates well with field resistance to Striga. F i e l d , trials were therefore conducted in the 1977 rainy season at A k o l a with a set of 50 germplasm lines and 40 F 3 lines. In these trials the field resistance and laboratory results did not correlate very well. The trial was repeated in the 1978 rainy season, and 96 low stimulant germplasm lines were planted in a Striga-sick field. A significant correlation coefficient of + 0 . 4 3 was found between field resistance and laboratory results. The
Field testing for Striga resistance. The International Striga Resistance Nursery (ISRN) has been a valuable tool to confirm resistance over locations. T w o international nurseries were dispatched to ten locations in five countries of the SAT. However, data were useful only from eight locations, since K o b o in Ethiopia, and Mwanihala in Tanzania reported very low Striga infestations. Details of the 59 entries tested in two trials for Striga resistance are given in Tables 15 and 16. It is Clear f r o m the results of Trial 1 that the response of varieties to S. hermonthica (African locations) and to S. asiatica (Indian locations) was different, indi-
Table 14. Sorghum material screened from July 1978 to June 1979 for low stimulant production for germination of Striga seeds. Group Caudatum—Kauras —Guinea —Bicolor —Dochna —Nigricans —Zera Zeras —Durra —Conspicuum —Membranaceum Subglabresense Subglabresense—milo Milo—Kauras Sudanense Sudanense Durra Sudanense Halepense Grain-grass Group unknown Total
22
Total
Low types
Percentage
119 19 8 40 225 23 87 45 3
16 4 0 0 3 0 2 0 0
13.44 21.05 0.00 0.00 1.33 0.00 2.29 0.00 0.00
47 2 78 103 1 1 256 3693
0 0 0 4 0 0 10 331
0.00 0.00 0.00 3.88 0,00 0.00 3.90 8.96
4750
370
Table 15. Results of ISRN-1 (rainy season, 1978). India Pedigree
Dharwar
Akola
Parbhani
Nandyal
SRN-484 N-13 IS-1464 IS-4202 IS-6942
X
† † † † †
X †
X †
X †
X †
X
X
555 IS-52-18 16-3-4 NJ-1515 IS-9985
† † X
† † † † †
X † X X †
X † † † X
IS-5106 IS-2203 SRN-4882B IS-8785 SRN-5790
X
† † † † †
X †
X †
X X †
X
X
† † † † † † † † X
† X † †
† †
† † † †
Ethiopia-2 (Cheffa) X X X X X X X X
Sudan-2 Sudan-1 (Abu Naama) (Abu Naama) X X X X X †
† † X X X
t X
X X X X
X X X X †
X X X
X X X X X
X X X X X
X X X X X
t t X X
X X X X X
X X X X X
X X X X X
X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X
† X
X † X X X X
X X
X X X X X X
X X X X X X
X X X X X X
Serena IS-2643 IS-4242 SRN-6838B (555 x 168)-22-l
† † X X
(Framida x 148)-21-2 (BC-9 x Bonganhilo)-24-1† (A-2377 x 555)-31-l (148 x 555)-13-3 23-4 (BC-9 x Bonganhilo)-25
X
(148 x 555)-31-l IS-5603 (M35-1 x 5S5)-20 (555 x 168)-33-4 (148 x 555)-29-3 CSH-1 (Control)*
† X X † X X
No of entries tested
32
32
32
32
32
32
32
No of entries selected
19
29
9
6
1
1
3
t
X X † †
† † † † †
† - Striga infestation less than 10% of control. x = Striga infestation more than 10% of control. * = CSH-1 was used as the susceptible control and taken as 100% infested.
23
Table 16. Results of ISRN-2 (rainy season, 1978). India Akola
Dharwar
IS-7227 IS-2404 IS-3962 x WABC 1022 IS-3968 IS-4270
X X * X X
*
Expt. 4/Ent-487 IS-2221 IS-2352 IS-2781 IS-2930
† † X * *
**
IS-3923 IS-3924 IS-4415 (Framida x IS-3691)-12-1 (NJ-2006 x Framida)-38-1
*
*
* † X † *
Pedigree
(148 x 555)-11 (M35-1 x 555)-21-3 (BC-9 x Boganhilo)-16-2 (M35-1 x 555)-16-l (M-35 x 555)-21-2
X † † † *
Ethiopia-2 (Cheffa)
Upper Volta (Ouagadougou)
† X X DR x X
X X X * X
DR x X X † **
X † X X *
† X * X
X X † † X
X X X X X
X X * † †
X X X * X
X X X * X
† X X X *
X * X X X
*
* X ** **
X * X X
(NJ-2006 x Framida)-18-2 (A2377 x 555)-12 (555 x 168)-9-l (555 x 168)-9-3 S-1464
* * * NT
X X † X NT
S-1510 S-1561 S-1488 S-1487 CSH-1 (control)
NT NT NT X X
NT NT NT X X
* X DR X
X † * X X
No of entries tested
26
26
30
30
No of entries selected
7
4
5
2
Note: Upper Volta was drought-affected area. Striga infestation was not severe. x = Less than 15% of control. OR = Drought resistant. †. = Less than 10% of control. * = Less than 5% of control. NT = Not tested. ** = Less than 1% of control.
24
eating the presence of a species-specific reaction of Striga on sorghum. Similar results were obtained in 1977. W i t h i n the Indian locations, the stability of resistance was poor. Only four entries (N-13, IS-4202, IS-5218, and IS-2203) showed Striga infestation less than 10% of control at all locations. In addition, SRN-4841, which exhibited resistance at all the locations tested last year, showed resistance only at A k o l a and one location in Sudan. However, it was susceptible in Sudan last year. In Trial 2, only one entry showed resistance across locations: a breeding line derived from a cross between M35-1 and 555. Breeding is in progress to improve the resistance of source material to Striga and to other undesirable agronomic traits.
Breeding for Resistance to Drought Efforts were made to screen for drought stress from the panicle initiation stage. Very low correlation was found between plant performance under stress and under adequate moisture conditions. This calls for development of a suitable experimental opportunity where drought can be expected and where adequate control of management is possible to reduce coefficients of variation (these tend to be higher in stress conditions). Useful material for the traditional farmer can be bred only if there is a good selection opportunity in drought conditions. The identification of needs and priorities to undertake this research improved considerably during the year.
Food Q u a l i t y In most regions where sorghum is utilized as a food, breeders select yellow or white grains with corneous endosperm. However, all such grains do not produce the desired food recipes satisfactorily. The complexity and diversity of sorghum foods popular across the S A T make it difficult for breeders to use empirical methods in the selection of quality grains suited for
several different preparations. Obviously, much information is needed to define precisely the physical and chemical properties of the grain that contribute to the satisfactory making of the various sorghum recipes. Evaluation of Chapati Quality Chapati is an unleavened bread popularly made in India from whole sorghum flour. An ideal chapati should taste good and remain soft for at least 10 hours at room temperature. Chapati evaluation using 13 physical attributes of the grain, dough, and the chapati itself have been standardized. Data collected on 1126 cultivars of diverse origin were analyzed statistically. The results reflect a broad range of variation for all the characters studied except grain density (Table 17). The kneading quality of the dough from various cultivars was classified subjectively into three grades by skilled women. Rolling quality of the dough, which varied from 15.00 to 27.87 cm, appeared to be a more reliable estimate of the dough property than the kneading score. Consistent differences were observed in chapati quality characters among cultivars. Environmental factors, such as soil, season, spacing, fertilizer, water availability, and percentage of moisture in the grain affect the grain properties, and consequently the chapati properties. It is important that comparisons be made only between entries sown at the same time and grown in a similar environment. Generally, chapati color, aroma, and taste are affected by the pigmentation on the pericarp. The color of chapati can also bias the panelist against its taste and flavor, and tannins of colored grains may lead to a bitter taste. Therefore, a subsample of 520 pearly white grain varieties f r o m the complete set of 1126 varieties was separately examined; it was found that within this group the range of variation for all the characters was as broad as that observed in the whole set of the material studied. The study revealed that corneous grains, in general, exhibited more breaking strength, had more density, absorbed somewhat less water, and showed better kneading and rolling pro-
25
Table 17. Variability for some grain and chapati quality attributes in sorghum. Range Attribute
Set a
Mean
±S.E
Minimum
Corncousncss score
I II I II I II I II I II I II
2.410 2.265 3.520 3.345 8.714 9.184 1.228 1.229 25.177 25.967 28.320 27.880
0.02 0.02 0.02 0.02 0.05 0.08 0.00 0.00 0.14 0.20 0.06 0.10
1.000 1.000 1.529 1.739 3.530 3.530 1.072 1.-112 13.080 13.080 20.580 20.580
5.000 4.000 7.115 5.820 18.800 18.800 1.437 1.437 41.770 41.770 36.910 34.350
I II I II I II I II I II I II
1.124 1.085 22.110 22.270 2.989 2.870 2.608 2.570 1.217 1.123 2.929 2.882
0.01 0.01 0.04 0.07 0.02 0.02 0.01 0.02 0.01 0.01 0.02 0.02
0.500 1.000 15.000 16.250 1.250 1.250 1.000 1.000 1.000 1.000 1.000 1.000
3.000 3.000 27.870 27.650 5.000 4.500 4.500 4.500 4.000 4.000 5.000 5.000
Grain wt (g/100 seeds) Breaking strength Grain density Water absorption (%) Water for dough (ml)
Kneading quality score Rolling quality (cm) Chapati taste Texture Flavor Keeping quality
Maximum
a. Set I had 1126 genotypes of various kernel colors. Set II had 520 pearly white seeded genotypes.
perties. Taste, texture, flavor, and keeping quality of chapatis from grains with 65 to 70% corneous endosperm were most desirable. Chapatis f r o m more highly corneous grains tend to be rough in texture, less soft, and poor in keeping quality, while the floury grains absorbed more water, kneaded poorly, and produced poor quality chapatis. Correlation coefficients between grain, dough, and chapati properties were computed from the data obtained f r o m 367 genotypes. Several of the characters were correlated at statistically significant levels, but the coefficients were weak. None of the characters was sufficiently correlat-
26
ed with chapati qualities to be used as an indirect assessment of chapati quality. A b o u t 800 selections in the F 5 and F 6 generations from the grain mold resistance breeding program were screened to identify superior chapati-making lines, using M35-1 as the check. The 59 selections found to be comparable were evaluated in the rainy season when M3S-1 (a dry-season variety) becomes pigmented and moldy and is very poor in chapati quality. Seven lines f r o m the wet season were found comparable to M35-1 grain produced in the dry season, paving the way to obtain M35-1 quality in rainy-season varieties.
Ugali Properties Ugali is a dumpling popularly made in Kenya from coarse flour. It is made either from whole sorghum flour alone or mixed with that of maize. Ugali preparation procedures were standardized with the help of five trainees from Kenya, and ugali-making properties of 90 sorghum varieties were evaluated by them. Cooking qualities of varieties showed significant differences. Mostly pale yellow or white ugali was preferred. Taste, texture, and keeping quality scores showed large differences for these characters among cultivars. In general, white corneous grains contributed to good ugali with less tackiness, a critical quality factor in ugali. M 3 5 - 1 , which makes excellent chapatis, was good for ugali also. However, E35-1, IS-5341, and IS-6928, which are more corneous and not particularly good for chapatis, exhibited the best ugali properties. The texture and keeping qualities of ugali f r o m floury grains were very poor. Uji Uji is a porridge made in Kenya from fine sorghum flour. After overnight storage, the porridge forms a gel, and its keeping quality is rated very good if the stored uji is thick, viscous, and the gel can disperse uniformly without clotting when heated with water. The keeping quality is rated poor if water separates out of the stored uji and/or the consistency of the gel is thin or heterogeneous. The keeping quality of uji could be quickly assessed by cooling the gel at 10°C for 3 hours. The gel was then removed from its container. The thickest gel retained the exact shape and nearly the diameter (58 mm) of the container (52 mm) when removed after cooling. Other gels varied in their shapes and extent of spreading, and their consistency could be expressed as the measured diameter on a linear scale. Gel diameters of 75 varieties varied from 58 to 112 m m . Gel diameter measurements of cultivars were characteristic and consistent and reflected the uji keeping quality. An association between ugali textural properties and measured
gel consistencies was also observed; the correlation coefficient was 0.74 and was statistically significant at 0.01 probability level. It appears that flours that make thick gels also tend to make ugali with acceptable texture (i.e., less sticky).
Selection Criteria for Improved Chapati and Ugali Qualities Grains with 65 to 70% corneous endosperm frequently exhibited the best chapati-making properties. Flour particle size indices of such grains were around 60 to 65, and gel consistency measurements were about 62 m m , indicating a reasonably thick gel. Grains with more than 70% of the endosperm corneous, particle size index values over 70, and a very thick gel consistency seemed most suitable for making ugali. Improvement for Lysine The high-lysine breeding project started at I C R I S A T in 1973 using the Ethiopian highlysine lines IS-11758 and IS-11167 which have shrunken seeds and approximately 70% increased lysine in the protein (3 to 3.5%). The single recessive gene hl was found to condition high lysine in these lines. Initially, selections with high lysine were recovered in normal-seeded segregates. However, selections in later generations resulted in very few lines with moderately high lysine. It has not been possible to find-nbrmal-seeded selections containing the hl gene. It appears that the high lysine and the shrunken seeds are conditioned by the same hl locus. This may frustrate breeding efforts to recover agronomically elite lines with high lysine in normal seeds. A second mutant source, P-721 (an opaque seed), came f r o m Purdue University in 1975. It was found that this mutant Alone produced an increase of about 30% in lysine as percent of protein (2.5 to 2.7%), and that derivatives with this level of lysine could be easily recovered from crosses involving P-721. Howeyer, when this line and derivatives including it as a parent were grown in environments where soil nitro-
27
gen was l i m i t i n g , no increase was observed in lysine percent of the protein. Yields of P-721 were also low and not responsive to fertilizers and better management. The response of P-721 across environments that differ in lysine as percent of protein is shown in Figure 1. As most farmers in the S A T w o r k with l o w fertility soils, it appears that the lysine percent of protein may be similar in normal and P-721-derived lines.
IS-11758
3.3 2.9
P-721 2.5
Mean CSH-1
2.1 1.7 1.9
Biochemistry Village-level surveys were made in seven states of I n d i a to identify the kinds of foods that are prepared f r o m sorghum. The states surveyed contribute more than 90% of the total area as well as production of sorghum in India. It was found that sorghum was used in breads, porridges, gruels, and as cooked, steamed, and fried foods, and snacks. The majority of people use sorghum to prepare unleavened bread called roti or chapati. Physicochemical characteristics of flour and chapati-making qualities of 24 sorghum cultivars studied (Table 18) showed considerable variations, and preliminary results are reported in Table 19. Flour qualities (water absorption, stickiness, and spreading ability of dough) were also studied and were evaluated subjectively. Chapatis were made to the same thickness and diameter under identical conditions and their quality was assessed by trained taste panel members for color, texture, flavor, taste, and acceptability. The relationship between physical and chemical characteristics and chapati qualities have been worked out. It appears that the quantity of solubles, fat, and ash in the flour
2.1 2.3 2.5 Environment means — Estimated lysine (%) in protein
Figure 1. Regression of estimated lysine (%) in protein in 3 of 22 entries tested across 12 environments during the 1977-78 postrainy season.
j o i n t l y influence and contribute to chapati characteristics (Table 20). Further analysis on the qualitative nature of other chemical parameters is in progress. Proximate composition and mineral analysis were determined on 100 selected germplasm collections grown at I C R I S A T farm during the same season. They represented the following types: w i t h luster; with persistent subcoat; completely corneous; almost corneous; intermediate; almost floury; completely floury; waxy endosperm; and w i t h white, yellow, straw, light b r o w n , b r o w n , reddish b r o w n , light red, red, grey, and purple seed coat colors. The analysis revealed wide variation in the values for different constituents in these samples (Tables 21 and 22). Grain maturation studies were conducted on
Table 18. Sorghum cultivars analyzed for physicochemical and chapati characteristics. CSH-6 M-32282 IS-7943
28
KARAD M-35082 M-36406 IS-9742
CS-3541 M-35088 BG-12 IS-9985
M35-1 M-35528 BG-30 IS-12611
P-721 M-35528 IS-2328 MOTI
E35-1 M-36135 IS-5090 555
Table 19. Physicochemical characteristics of flour and quality of chapatis made from sorghum.a Component
Range
Mean
4.5- 6.9 7.2-10.6 14.6-25.3 66.0-74.1 65.5-69.0 21.9-30.0 3.1-10.5 1.2- 2.1 9.3-15.6 0.5- 0.8 2.6- 4.2 1.4- 1.9
5.7 9.2 20.0 70.0 66.4 27 .7 6.6 1.3 11.8 0.7 3.0 1.6
66.0-90.0 16.9-39.6 1.0- 3.9 1.2- 3.8 1.5- 3.2 1.4- 3.2 1.4- 3.3
76.8 28.0 2.8 2.5 2.5 2.5 2.5
FLOUR Swelling capacity v/v v/w Flour solubles (%) Starch (%) Gelatinization temperature(°C) Amylose (%) Water-soluble amylose (%) Sugars (%) Protein (%) Water-soluble protein (%) Fat (%) Ash (%) CHAPATI Water for dough (ml/100 g flour) Moisture loss during baking (%) Color and appearance b Texture b Taste b Flavor b Acceptability *
a. Based on an analysis of 24 cultivars. b. Ratings given by panelists (4 = excellent: 3 = good; 2 = fair; 1 = poor).
Table 20. Assessment of chapati qualities as a function of chemical characteristics.a Flour characteristics Chapati qualities
Solubles
Color Texture Taste Flavor Acceptability
-0.33 b -0.22 b -1.03* -0.96* -1.62 c
Fat -1.39* -0.79 d -0.13* -0.18 c -0.16*
Table 21. Proximate composition of selected sorghum germplasm samples.a Constituent
Ash - 2.88c - 1.00 -0.82 - 1.21d -0.91 b
a. Multivariate regression analysis: Chapati qualities as dependent variable tested against physicochemical characteristics as independent variables. b. Significant at 0.01 c. Significant at 5% d. Significant at 10%
Starch (%) Protein (%) Sugars (%) Ether extract (%) Crude fiber (%) Ash(%) Lysine (g/100 g) Tannin (%) 100-seed wt (g) Grain hardness, force required to break (kg)
Range
Mean
55.6-75.2 10.6-14.1 0.8- 4.2 2.1- 7.6 1.0- 3.4 1.6- 3.3 1.37-3.39 0.1- 6.4 1.3- 5.7
70.8 14.1 1.3 3.3 1,9 2.1 1.7 0.6 2.*
1.8-10.4
6.5
a. n = 100, moisture-free basis.
29
C S H - 1 , CSH-8, M 3 5 - 1 , P-721, CSV-3, Ry-49, IS-11167, and IS-11758. Samples from each of these eight cultivars were collected from 7 to 49 days following 50% flowering at weekly intervals and were analyzed for dry matter, starch sugar, protein, fat, and ash. D r y matter accumulation increased up to 28 days; then it declined in the cultivars tested. An increased rate of accumulation of starch was noted in cultivars M35-1
Table 22. Mineral and trace element analysis of sorghum germplasm samplesa (mg/100 g). Element Phosphorus Magnesium Potassium Iron Copper Zinc Manganese
Range
Mean
388 -756 167.2 324.7 363 -901 4.70- 14.05 0.39- 1.58 2.49- 6.78 0.68- 3.30
525.5 211.6 536.5 8.48 0.86 3.91 1.75
and CSV-3 up to 21 days, and did not change appreciably after that stage. While starch tended to accumulate, the sugar content decreased (Fig. 2). Protein accumulation was rapid in the initial stages for all the cultivars except Ry-49 and the two high lysine Ethiopian lines in which a very slow increase was observed. Studies on soluble sugars using Biogel P-2 column were carried out on ten cultivars. Stachyose, raffinose, sucrose, and glucose 4fructose were identified; their values ranged from 0.04 to 0.2, 0.1 to 0.4, 0.9 to 3.9, and 0.06 to 0.7%, respectively. Studies on physicochemical and chapati characteristics will be continued using more cultivars in order to test our initial findings. Efforts will be made to improve our taste panel evaluation procedures.
M 35-1 RY-49
a. n = 99 on a moisture-free basis.
I S - 11758 Sugars (%) 80
Promising sorghum varieties are evaluated for chapati quality in the laboratory at ICRISAT Center.
Starch (%)
70
10 8
60
6 50
4 2
40 7
14 21 28 35 42 D a y s from 50% f l o w e r i n g
49
Figure 2. Changes in starch and soluble sugars content in maturing grains of three sorghum cultivars.
30
Physiology
240 210
Drought Resistance Using the line source sprinkler irrigation technique (LS) we conducted experiments to evaluate 1. the relationships between soil-water (irrigation plus soil moisture) and crop growth, development and yield, and 2. the usefulness of the technique for screening sorghum genotypes for drought resistance. Nine genotypes were sown in Alfisol during the postrainy season. Each side of the LS f o r m ed one replication, and these genotypes were randomized w i t h i n each replicate. The field was uniformly irrigated (using perfo-spray) until the boot stage was reached in the genotype CSH-6. The LS was used at 50, 6 1 , and 77 days after sowing to create a gradient of soil moisture (stress). The amount of water received across the plot was measured in catch cans placed at crop height. Measurements of growth, development, and plant height were also made during the treatment period, and the grain yield and total biomass were determined at harvest. Environmental measurements, made in collaboration with the Farming Systems Research Program, included leaf-water potential, leaf rolling, and leaf temperature. Soil moisture and potential evaporation were also measured. Figure 3 shows the cumulative water applied using LS and the calculated evapotranspiration (Et) after the first LS irrigation u n t i l maturity. The effect of a continuously declining plant and soil water status on leaf-air temperature differences in CSH-6 is also shown. The response of the different genotypes to the water stress gradient is shown in Figure 4. The genotypes w i t h i n the same maturity class are shown by similar lines. A comparison of the genotypes in the early maturity group ( C S H - 1 , CSH-6, and IS-1037) shows clearly that CSH-1 had the greatest yield potential tinder low stress conditions but that IS-1037 showed the least sensitivity to change in drought stress. In the
Y = 229.81-9.12X (r = 0 . 9 4 , P < 0.001) Evapotranspiration
2
180
0
150 120
-2
90 60
-4
30 0 2 4 6 8 10 12 14 Distance from line source (m)
Figure 3. Total amount of irrigation water received, evapotranspiration (beyond 50 days until maturity), and leaf-air temperature differences at various distances from line source of sorghum (1978-79 postrainy season).
medium group, CSV-5 and CS-3541 were not distinguishable but were higher yielding than V-302. In the later group, CSH-8 and SPV-86 were similar and showed a considerably better yield potential than M 3 5 - 1 , although the latter was less sensitive to changes in stress.
Charcoal Rot Resistance The line source sprinkler irrigation technique was also used to study the effect of increasing soil moisture stress on charcoal rot incidence. Figure 5 shows that the disease increased w i t h soil moisture stress. I n i t i a l results f r o m both experiments are encouraging and it is hoped that current experiments w i l l confirm the usefulness of the LS technique and that it can be used subsequently by breeders and physiologists to select for drought and disease resistance. The possibilities of using this technique to study the interaction between fertility status and soil moisture w i l l also be investigated w i t h selected genotypes.
31
450
Early maturity Medium maturity Late maturity
400
CSH-1
350 SPV-86
The presence of trichomes on the leaf surface appears to confer an advantage in t w o ways: (1) by reduction in the amount of egg-laying on the leaf, and (2) by a reduction in the frequency w i t h which the presence of eggs results in the death of the shoot (Fig. 6). The ultimate percentage of plants w i t h deadhearts was 24 and 54 for the trichomed and trichomeless lines, respectively.
CSH-6
300
IS-10.37 250 CSH-8 200 CS-3641
CSV-5
150 100 V-302 50
M35-1
0
2 4 6 8 10 12 Distance from line source (m)
reduced (e.g., 85% vs 95% deadhearts), but differences were statistically significant in all cases. Under lower and more realistic levels of attack, the differences between the two groups were both agronomically and statistically significant (e.g., 18% vs 35% deadhearts).
14
Intercept of regression line = yield potential Slope of line = rate of yield change with water stress Area under line = mean yield over range of stress Figure 4. Effect of decreasing soil moisture on sorghum grain yield (line source; 197879 postrainy season),
A field evaluation of the leaves of trichomed lines showed certain distinctive characteristics in the seedling stage. They tended to be erect and narrower w i t h a yellowish green, glossy appearance. Such leaves are referred to as "glossy." These traits are evident in the first 3 weeks following emergence; later, however, leaves do not show these distinctive characteristics. Approximately 8000 lines of the w o r l d sorghum germplasm collection were screened for the presence of this glossy seedling trait. Only 70 such lines were found, and these are largely of South Indian origin. Of these 70, more than
65
Resistance t o Shoot F l y
(r=0.89, P 0.05) 7.02(P> 0.61)
33
w i t h red soil (Alfisol) up to 5 cm f r o m the top. The soil was saturated at sowing and then allowed to slowly dry out. Portable shelters were used to keep out the rain. The lines were rewatered when they appeared to be w i l t i n g ; only 50% of them showed chances of recovery on rewatering. A visual score on a 1 to 5 scale for severity of wilting was made prior to rewatering the plants. This was repeated 1 and 5 days later, so as to assess the ability of the different lines to recover. Preliminary results f r o m 82 lines showed signi-
ficant differences in tolerance to water stress at the seedling stage. The results also suggest that there is scope for selection for genetic improvement.
Entomology D u r i n g the year under review it was possible to provide graded levels of shoot fly attack on breeders'material. Studies on the biology and
Trichoma glossy
Trichoma nonglossy
Trichomeless glossy
Trichomeless nonglossy
100 90
E x p e r i m e n t I (135 e n t r i e s )
E x p e r i m e n t I I (131 e n t r i e s )
80 70 60 50 40 30 20 10 0 Combination I
II
III
IV
I
II
III
IV
V
100 90
E x p e r i m e n t I I I (120 e n t r i e s )
E x p e r i m e n t IV (120 e n t r i e s )
80 70 60 50 40 30 20 10 0 Combination 1
II
III
IV
I
II
III
IV
Figure 7. Distribution pattern of various trichome-glossy combinants indicating level of shoot fly tolerance in different experiments on sorghum.
34
ecology of the shoot fly and stem borer were continued. A full-scale laboratory for stem borer rearing on an artificial diet was started, and a large group of materials was screened successfully using the dispenser technique developed by C I M M Y T . Further studies on stem borer pheromones were carried out.
Pest Incidence and "Carryover" Studies Observations on pest incidence and carryover of pests f r o m the previous season were made both at I C R I S A T Center and on farmers' fields. The standard observation plots consisting of a range of cultivars were grown in the pesticidefree area of I C R I S A T Center in both the rainy and, for the first time, postrainy seasons. Shoot fly (Atherigona soccata) was severe in the rainy season, and there was a heavy stem borer attack by two species, Chilo and Sesamia, in the postrainy season. Observations on the stalk residues of sorghum f r o m the rainy season confirmed that some larvae could survive up to 250 days and that 44% of the larvae entering diapause produced adult moths. Parasitism in larvae was low (about 5%). The number of larvae present in stalks was proportionally far higher at I C R I S A T Center than on farmers' fields, and there was an indication that, as a percentage, more of the larvae f r o m farmers' fields survived to produce adults. Although no parasites were obtained f r o m larvae f r o m farmers' fields a large number of parasite pupal cases were present.
Sorghum Shoot Fly W o r k continued on shoot fly population dynamics using galvanized square pan metal traps with fishmeal at 20 different sites at I C R I S A T Center for sampling of cropped and grassland areas. The results f r o m these studies were similar to those obtained in 1977-78; 30 species of the genera Atherigona and Acritochaeta were recovered. Trap catches in A p r i l , M a y , and June were extremely low, but a significant proportion
of the flies caught were A. soccata. Detailed examination of 45 female A. soccata caught in June indicated that most were spent; however, 38% had a second or third batch of developing eggs. No gravid females were found in the sample but 20% were virgin or w i t h a first egg batch. An examination of 2936 A. soccata females trapped in July showed that 47% had well developed ovaries and that 4% were gravid. A significant number (46%) were spent. Only 3% were virgin or with a first batch of developing eggs. These figures therefore did not indicate any lack of attraction to older flies, but there was strong evidence that flies w i t h maturing ovaries were highly attractive. The fact that the low M a y population was capable of producing a high number of eggs was confirmed by studies in which sorghum was sown at eight sites at I C R I S A T Center on three different dates in the summer season (May) and irrigated. The m i d - M a y sowing was heavily attacked by shoot fly ( 2 1 % of seedlings with eggs). Activity was apparently stimulated by an unseasonal rain (about 77 mm) on 11 and 12 M a y 1979. Studies on 17 species of grass at I C R I S A T Center showed that although a very extensive range of shoot fly species was present, only seven species of grass carried A. soccata and the number of flies bred f r o m these was extremely low. The tendency for a particular fly species to be associated with relatively few grass species was confirmed. Three of the 13 fly species bred f r o m grasses remain undescribed (Table 24). A preliminary attempt to determine if shoot fly moved over long distances indicated that there was little movement f r o m sorghum fields when a trap was placed in the middle of a lake 1 km f r o m the nearest sorghum for 2 months at the peak sorghum shoot fly season. Only four A. soccata were caught in 2 months of observation. In a study in which five species of w i l d sorghum and sudangrass were sown in the postrainy season, A. soccata was the dominant species present in damaged plants (Table 25). Three other fly species Atherigona atripalpis, A. bidens, and A. oryzae, were bred in very low numbers. The w o r k on breeding shoot flies f r o m cultivated
35
these studies, it is clear that carryover of A. soccata between seasons is closely related to the presence of sorghum, either w i l d or cultivated. Preliminary studies on fishmeal fractions continued, in association with the M a x Planck
sorghum continued and again 98% of the male flies bred (13 222) were A, soccata. Six other species were bred f r o m sorghum, including one unidentified species, but the numbers were extremely l o w ; Atherigona falcata and Acritochaeta orientalis were more numerous. F r o m
141 2 19 12 4 3
131 10 8 11 5 0
Grand Total
3604 2031 1573
SP XIV
272 12 27 ' 23 9 3
SP VII
Eriochloa procera Panicum repots Setaria glauca Setaria intermedia Setaria italica Unidentified grass
SP III
60 3 127 808 229 57
atripalpis
69 9 180 990 334 115
eriochloae
129 12 307 1798 563 172
reversura
Cynodon dactylon Dichanthium annulatum Digitaria adscendens Echinocloa colonum Echinocloa crusgalli Eragrostis japonica
pulla
6 29 28 16 45
oryzae
4 25 41 26 57
punctata
No. of males
10 54 69 42 102
falcata
No. of females
Bothriochloa pertusa Brachiaria distachya Brachiaria eruciformis Brachiaria ramosa Brachiaria reptans
soccata
Name of the host
Total flies
Table 24 Shoot flies and their host plant records (other than sorghum) from 1 June 1978 to 31 May 1979.
6 4 28 2 12 2 42 1 1
1 24 1
1 1
1
16 1 5
1 5 782 227 1
1
1
2
1
1
51
7
1 121 6
1 3 1
50
2
1
71 9 1 1 1
2
54 1 3 10
5
26
1022 96
6 183 83 52 57
7
15
1
1 24
Table 25. A range of shoot flies bred from wild sorghums and sudangrass during postrainy season 1978-79. Name of the host Sorghum almum Sorghum halepense Sorghum virgatum Sorghum verticilliflorum Sorghum arundinaceum Sorghum sudanense Grand Total
36
Total flies
Females
Males
soccata
bidens
oryzae
atripalpis
66 204 55 111 2 35
33 101 23 68 2 27
33 103 32 43 0 8
32 102 31 43 8
1 -
— 1 -
— 1 -
473
254
219
216
1
1
1
Institute. To date the catches with different tractions have been lower than with whole fishmeal. Screening of germplasm lines collected rerently in India under high levels of fly attack continued. In all, eight trials were conducted in the rainy season and four in the postrainy season. In addition, in the postrainy season when fly attack is naturally high, several trials were carried out without spreader rows and fishmeal. Lines were evaluated on the basis of oviposition nonpreference, deadheart percentage, tillering ability, and head production. Eighty-five lines f r o m the rainy season and 194 from the postrainy season were selected for further testing.
160 150
Light trap catch Pheromone catch
140 130 120 110 100 90 80 70 60 50 40 30
Stem Borer The spotted stem borer, Chilo partellus, is an important pest of sorghum in India and in the lowland areas of East Africa. The distribution and biology of the pest species have been worked out. In addition to the "carryover" studies, regular monitoring of C. partellus at I C R I S A T Center was continued using light traps and pheromones. T w o periods of activity were identified—one in August/September and the other, far more important, in January/February/March. The increase of catches of male moths in the pheromone traps in A p r i l is probably associated with the harvest of the postrainy season crop (Fig. 8), but this needs further investigation. M a n y of the pheromone traps were sited near sorghum fields. In spite of the large numbers of moths present in M a r c h / A p r i l , "carryover" was contained, possibly by enforcement of a closed season. Further studies on the pheromones of C. partellus were carried out. The pheromone was found to be composed of aldehyde (major) and alcohol (minor) components. The studies indicated that very low dosages (5 μg) of the alcohol and aldehyde components were inferior to a load of 50 μg. The aldehyde component was the major attractant: the treatments not including the alcohol component caught far more moths. A preliminary study of m o t h activity at night, w i t h
20 10 0
Months Figure 8. Mean monthly catches of male Chilo partellus moths at light (3) and pheromone (14) traps at ICRISAT Center, June 1978 to May 1979. pheromone and virgin female moths, was carried out for seven nights in the postrainy season (February). It was found that the m o t h activity was greatest between midnight and 0300 hours. Some activity, however, was also observed as early as 2100 hours (Fig.9). The maximum calling activity of females was between 0100 and 0200 hours. Interestingly, in the period immediately prior to this (midnight to 0100 hours), the synthetic pheromone attracted more moths indicating that males were receptive, but that females were just beginning to " c a l l " and probably not producing sufficient pheromone to dominate. Further w o r k in this area is required since temperature effects are undoubtedly important. Some 258 germplasm entries were screened for resistance to stem borer in both the rainy
37
Synthetic pheromone 50
One-day-old virgin female
40 30 20 10 0
Pest Nurseries The 1978 pest nurseries were distributed to cooperators within India and overseas. The shoot fly nursery was sent to 13 locations, the stem borer nursery to 12 locations, and the midge nursery to 8. The number of successful returns was not encouraging, but at sites where records had been adequately taken, it was clear that the entries selected by our program showed higher degrees of resistance than local check entries. Some of the midge lines, in particular, were promising in M a l i and Upper Volta.
Pathology Hours Figure 9. Mean nightly catch of Chilo partellus male moths with synthetic pheromone and virgin female attractant over seven nights (14 to 20 February 1979; totals of three replicates) .
and postrainy seasons. Larvae produced on artificial diet were used for field screening. The newly established rearing laboratory allowed 4 ha of breeders' material to be infested. In all, 85 lines representative of India, Kenya, Ethiopia, and Sudan were selected for further screening.
Other Pests Levels of midge attack were low at I C R I S A T Center and selection pressure was insufficient f o r adequate screening of the midge nursery. Lines S-Girl-MR-1 and AF-28 were, however, retained for further testing. Of the 101 lines found to be less susceptible to earhead bug, Calocoris angustatus, in the previous monsoon season, most were eliminated by a field-screening technique dependent on the high natural levels of infestation obtained on July-sown material. Only 14 were retained for further study.
38
The major emphasis in sorghum pathology was on the identification and utilization of stable host-plant resistance to grain molds (species of Fusarium, Curvuiaria, and Phoma), charcoal rot (Macrophomina phaseolina [Tassi] Goid.), downy mildew (Peronosclerospora sorghi [West & Uppal] C. G. Shaw), and the leaf blight (Exserohilum turcium [Pass.] Leo & Sugg.) and rust (Puceiniapurpurea Cooke). Grain molds are a major problem of widespread occurrence, particularly on short-cycle sorghums, which often mature under wet conditions. Considerable progress was made in developing elite sorghums with mold resistance. These materials are contributing to national and regional programs in S A T areas. G o o d sources of resistance to charcoal rot, downy mildew, leaf blight, and rust were identified. Multilocational testing was conducted for the third year for grain molds, downy mildew, and leaf diseases at many locations in Asia, Africa, and the A m ericas.
Grain Mold Resistance Screening At I C R I S A T Center. Artificial inoculation and natural infection were both used in screening for resistance to grain molds. In artificial i n oculation a mixture of Fusarium moniliforme Sheld., F. semitectum Berk & Rav., and Curvuiaria lunata (Wakker) Boedijn was used as
inoculum. These were the most prevalent fungi previously isolated f r o m molded grain. Figure 10 shows the steps used in grain mold resistance screening. Field screening. Of 30 entries screened in the 1978 International Sorghum Grain M o l d N u r sery ( I S G M N ) , 12 entries were selected (Table 26). Eighty-two singlehead selections from progeny in the advanced screening program were evaluated in the laboratory; of these, 17 were rated as less susceptible. Other than the 12 entries selected in the I S G M N , only 4.6%
ENTRIES FROM NATIONAL AND REGIONAL PROGRAMS
of the lines in the 1978 International Sorghum Disease Nurseries ( I S D N ) were selected since they were not developed on a m o l d resistance background. A m o n g the source material, a group of seven entries (IS-14332, IS-2327, E35-1, IS-9225, IS-2328, IS-2261, and IS-2435) performed consistently better than others during the past 3 years. Laboratory screening. Field screening for grain mold resistance allows only one screening in a year and the success of the screening is dependent on favorable weather conditions during
I N I T I A L F I E L D SCREENING (RAINY SEASON)
SORGHUM GERMPLASM
SINGLE-PLANT SELECTIONS
SEED INCREASE (POSTRAINY SEASON)
LABORATORY SCREENING (SUMMER SEASON)
ADVANCED F I E L D SCREENING (RAINY SEASON)
MULTILOCATIONAL TESTING
U T I L I Z A T I O N PHASE MOLD RESISTANCE BREEDING PROGENIES
NATIONAL AND REGIONAL PROGRAMS
FARMERS IN SEMI-ARID TROPICS Figure 10. Flow chart of sorghum grain mold resistance screening activity at I C R I S A T Center.
39
Table 26. Summary of the grain mold resistance screening activities on sorghum at ICRISAT Center during rainy season 1978.
Material ISGMN 1978' SEPON 1978c Less susceptible lines from laboratory screening International nurseries other than ISGMN-1978 Elite selections from mold resistance breeding project Single head selections from rainy season 1977 Mold resistance breeding progenies F3 and F4 Total
Entries screened
Entries selected
Percent entries selecteda
30 48
12 6
40.0 12.5
82
17
20.7
109 111
5 11
4.6 9.9
564
112
19.9
2096
223
10.6
3040
386
12.6
a. Based on field head mold ratings of 2. b. The 1978 International Sorghum Grain Mold Nursery. c. The 1978 Sorghum Elite Progeny Observation Nursery.
flowering and maturity. Therefore we tested a laboratory screening technique to differentiate the grain in the laboratory for apparent low and high susceptibility to grain molds. The technique involves incubation of postrainy-season-harvested grain in petri-plate moist chambers at 25°C for 4 days and measurement of three grain m o l d infection parameters: (1) percent m o l d (percentage of molded grain after incubation), (2) severity (moldiness of each grain on a 1 to 5 scale), and (3) visual scoring (assessment of moldiness on the incubated grain). A m o n g the 659 entries screened in the laboratory in summer 1978, no single entry was completely free of m o l d infection, although 77 entries had visual scores of 2 or less. Multilocational testing. The objective of this program is to develop stable grain m o l d resistance, to distribute source material to interested scientists, and to promote the development of a cooperative international network of scientists.
40
In the 1978 I S G M N (Table 27), no entry was highly resistant, and eight entries—IS-14332, IS-9225, E35-1, IS-2328, IS-2327, JP-2579, M-36284, and M-36285—were consistently better than others at most locations. The two Mlines are derivatives f r o m SC-108-3 and E35-1. Grain molds are greatly influenced by humidity at the time of flowering. Late flowering entries generally tend to escape mold infection. H o w ever, several of these entries performed substantially better than the susceptible check (IS-9991), even though they flowered earlier or about the same time.
Charcoal Rot (Macrophomina phaseolina) At I C R I S A T Center. Using the toothpickinoculation technique, 540 sorghum germplasm lines and 1501 breeding progenies were screened for resistance to charcoal rot. Individual
Table 27. The rank values of 30 ISGMN-1978 entries based on across-location means for three grain mold assessment parameters. Entry
Heads of the mold-resistant variety E35-J. This variety was seleeted from the ISGMN and is performing well in Upper Volta.
plants were split open at maturity and the internal spread of the pathogen from the internodal point of inoculation near the base of the plant was assessed on the basis of number of nodes crossed. There were 399 lines that had no node crossed in any plant; 644 lines had up to 50% of the plants showing one node crossed. In the advanced screening of 2918 F 3 charcoal rot resistance breeding progenies, 2281 single plants were selected by breeders as having good agronomic traits (Table 28). When the selected plants were split open, 567 had one node crossed and only 26 plants showed no spread of infection from the point of inoculation. A l l other plants showed spread of infection within the inoculated internode. The toothpick-inoculation technique causes physical injury to plants and is therefore unsatisfactory for disease resistance screening. Better inoculation methods are under investigation. Problems have also been encountered at I C R I SAT Center with occasional rains in November and February that disturb the moisture stress conditions essential for infection and development of charcoal rot. A more suitable location for initial screening of a large volume of sorghum material is being sought.
Field rating''
Lab rankingb Lab ratingc
IS-14332 1S-9225 E35-1 IS-2327 M-36284
1 2 3 5 6
1 4 7 3 6
4 2 3 1 7
IS-2328 M-36285 JP-2579 IS-2435 1S-2261
8 10 9 7 4
8 2 9 5 12
5 6 10 13 18
M-36368 M-36471 M-36423 M-36533 IS-472
11 12 13 14 15
16 15 17 20 14
16 17 8 9 10
M-36348 M-36049 M-36046 M-36619 CS-3541
16 17 18 19 20
11 18 22 10 24
14 11 22 12 23
M-35052 M-36109 M-36113 M-407-15 M-35175
21 22 23 24 25
13 25 19 23 28
15 26 25 20 28
M-36333 M-4337-2 M-4397-1 IS-9991 (check) PP2B (check)
26 27 28 29 30
26 27 21 30 29
24 27 21 30 29
a. Based on data from 12 locations scored on a 1 to 5 basis. b. Based on data from 9 locations- based on a simple ranking. c. Based on data from 8 locations based on estimated percentage of molded surface of threshed grain.
Multilocational testing. The International Sorghum Charcoal Rot Nursery (ISCRN) was initiated to identify sources of stable resistance to charcoal rot and to distribute resistant genotypes to scientists in national and regional
41
Table 28. Number of single-plant selections in each charcoal rot reaction category for no node crossed and one node crossed in charcoal rot resistance breeding progenies of sorghum.
Group of material Rabi* sorghum breeding progenies (F3s)-I Charcoal rot resistance breeding progenies (F3s)-I Rabi sorghum breeding progenies (F 3 s)-II Charcoal rot resistance breeding progenies (F 3 s)-III Total
Total entries screened
No. of single plant selections
Reaction category (No node crossed) X
Y
Z
One node crossed
568
133
2
1
89
41
352
950
5
21
623
301
1000
337
9
20
231
77
998
861
10
59
664
148
2918
2281
26
101
1587
567
a. No node crossed plants were again subdivided into three categories X, Y. and Z based on extent of stalk colonization within inoculated node, where X = no spread from inoculation point. Y = about half of internodal area covered and Z = extending up to one internode but not crossing any node. b. Rabi = postrainy season.
programs. Based on the mean performance of entries at seven locations in Afric a and Asia, eight entries had a m i n i m u m mean number of nodes crossed of less than one (Table 29), but the maximum mean number of nodes crossed for these entries ranged f r o m 2.4 to 8.4. The known high susceptibles had up to seven nodes crossed. At Nandyal, where the m a x i m u m disease pressure was recorded, four entries—(SC-108-4-8 x CS-3541)64, CSV-4, (SC-108-4-8 x C S - 3 5 4 1 ) - l l , and I S - 1 2 1 - p e r formed better than other test entries based on mean number of nodes crossed and percent softstalked plants. The check entries at Nandyal had a mean of up to seven nodes crossed.
charcoal rot reactions (mean number of nodes crossed), confirmed earlier observations: 1. Resistant and susceptible entries flowering around the same time differed in their charcoal rot reactions at locations where the rainfall received was low (10 to 40 mm). 2. Resistant and susceptible entries showed almost the same reactions at locations where the rainfall received was high during flowering to maturity (110 to 196 mm), w i t h the exception of one replication at Parbhani. The low susceptible entry at Parbhani had no nodes crossed in one replication and in another replication up to three nodes were crossed.
The total rainfall received during the period f r o m flowering to maturity at various locations was found to influence the expression of charcoal rot symptoms (Fig. 11). In a study of known high and low susceptibility entries, two interesti n g points, observed in comparison of total rainfall received, days to 50% flowering, and
Leaf Blight (Exserohilum turcicum) and Rust (Puccima purpurea)
42
Large-scale field screening for resistance to
leaf blight and rust was carried out at I C R I S A T Center. Inoculum grown on autoclaved sorghum grain was used to promote leaf blight incidence, and severe natural incidence was
relied on for rust screening. Of the 930 lines in preliminary screening, 125 were blight-free and 40 rust-free. An additional 480 entries had trace to 5% blight, and 303 entries had up to
Table 29. Charcoal rot reactions (mean number of nodes crossed) of the 1978 ISCRN entries at seven locations.
Entry
Mean days to 50% flowering
Mean number of nodes crossed Min a
Maxa
Nodes crossedb < 1
(SC-108-4-8 x CS-3541)-64 20-87 1-30 (SC-108-3 x CS-3541)-30 CSV-4
63 63 68 73 70
0.6 0.8 0.8 0.8 0.8
3.3 3.2 4.4 3.0 3.3
10 8 9 8 8
8-55 (SC-108-4-8 x CS-3541)-11 IS-121 IS-1235 4-45
63 65 58 69 64
0.8 0.9 0.9 1.0 1.0
5.2 3.3 2.4 4.0 8.2
9 7 10 6 8
SC-120-14 6-39 5-33 15-36 4-20
65 66 69 61 67
1.0 1.1 1.1 1.2 1.2
3.9 4.8 5.0 6.6 5.5
5 8 8 8 6
IS-12666 C 18-10 4-22 23-94 2-86
56 69 66 65 65
1.3 1.3 1.3 1.3 1.4
4.8 4.8 3.8 5.0 7.6
6 6 5 7 8
21-78 20-67 1-52 IS-84 SC-120
62 67 69 65 64
1.4 1.4 1.5 1.5 1.5
5.0 6.2 4.6 8.4 5.4
7 8 7 7 6
25-98 21-82 IS-410 CSH-6c A-2268c
63 64 58 61 71
1.6 1.6 2.1 2.2 2.4
5.2 6.6 5.8 7.4 5.8
7 6 3 5 3
a. Data based on seven locations—Wad Medani, Tarna. Kamboinse. Parbhani. Dharwar, Nandyal,and ICRISAT Center. b. Two replications at each of the seven locations, c. Known high susceptibles.
43
7 6 6
CSH-6
4 3 2 1 0 200
(SC 108-4-8 X CS 3541)-64
150 100 50 o 80
(SC 108-4-8 x CS 3 5 4 1 ) - 6 4
60 40
CSH-6
20
Downy Mildew (Peronosclerospora sorghi)
0
Figure 11.
Total rainfall received from flowering to maturity; days to 50%flowering and charcoal rot reactions (mean nodes crossed) of a known highly susceptible —CSH-6—and a less susceptible— (SC 108-4-8 x CS-3541]-entry of sorghum in the 1978 1SCRN at three Indian and two African locations.
5% rust. Only 14 entries-IS-2007, IS-3679, IS-3872, IS-3911, IS-6958, IS-9836, IS-10803, IS-9928, IS-1201C, IS-3579C, IS-3818C, IS684SC, IS-7254C, and IS-7994C-were free f r o m both blight and rust when scored at the soft dough stage. International Sorghum Leaf Disease Nursery. The International Sorghum Leaf Disease
44
Nursery ( I S L D N ) has three objectives: (1) to identify stable resistance sources to various leaf diseases of which the most important are anthracnose (Colletotrichum graminicola [Cesati] Wilson), grey leaf spot (Cercospora sorghi Ellis & Eberhart), leaf blight (Exserohilum turcicum [Pass] Leo. & Sugg.), rust (Puccinia purpurea Cooke), sooty stripe (Ramulispora sorghi [Ellis & Eberhart] Olive & Lif.), rough leaf spot (Ascochyta sorghina Sacc.) and zonate leaf spot (Gloeocercospora sorghi Bain & Edg.), (2) to identify " h o t - s p o t " locations for screening under natural infection for these diseases, and (3) to distribute the leaf disease resistance source to cooperating scientists in countries o f the SAT. Table 30 shows the results of the 1978 I S L D N . IS-7254 was the best entry (it has been for 3 successive years), but none of the entries showed a high level of resistance to a particular disease at all locations.
We continued efforts at I C R I S A T Center to develop an effective screening technique for sorghum downy mildew ( S D M ) . In order to provide continual sporangial inoculum, several cultivars of maize (Zea mays) and teosinte (Euchlaena mexicana) were tried as infector rows. Although a considerable number of plants in these cultivars developed systemic infection, the conidial production was not sufficient to serve as an effective source of inoculum. Preliminary studies were conducted with sorghum (known high susceptibles CSV-2, DMS-652, and IS-2550), maize (CM-500), and sweet corn. These plants were grown in trays w i t h sterilized soil and placed between previously sown infector rows. Y o u n g seedlings developed high levels (67 to 88%) of systemic infection. However, this infector row technique was not effective for large-scale field screening because we could not control shoot fly attack in the latersown test entries.
Mixtures of oospores and soil with farmyard manure (approximately 1:10-oospore:soil by volume) produced S D M infection of 60% in the known highly susceptible DMS-652 sorghum cultivar. The combination of oospores applied in the soil and later inoculation with conidia may help in obtaining high levels of S D M infection. Up to a mean of 53% systemic infection was obtained when conidial suspension was injected into 29 to 34-day-old plants of DMS-652.
Microbiology Ninety-eight cultivars of sorghum were screened for their nitrogenase activity using an acetylene reduction assay during the rainy season and the irrigated winter (postrainy) season of 1978— 79. Nine out of the 65 cultivars planted in the winter season stimulated nitrogenase activity of more than 30 μg N/15-cm dia core per day (Table 31). Only two lines had above 235 μg
Table 30. Flowering data and maximum reactionsa of 23 sorghum entries to seven leaf diseases* at various locationsc in the 1978 I S L D N . Entry
MDTFd
Blight
Grey
Anth.
Zonate
Rust
Rough
Sooty
91 100 72 69 64 79
3 3 3 3 4 4
3 3 4 3 5 4
2 3 5 3 5 4
3 4 4 3 4 3
2 2 2 3 3 2
1 2 2 2 3
3 2 2 2 2 2
SC-120-4 IS-10240 IS-4150 IS-3925 IS-115 SC-326-6
67 66 76 72 73 83
3 2 3 4 3 3
3 4 3 4 4 3
3 4 4 4 3 3
5 4 4 3 3 4
2 3 3 3 3 2
4 3 2 2 4 4
2 3 3 3 2 3
IS-2419 IS-10262 IS-517 IS-460 IS-158 IS-152
60 60 61 56 65 61
3 3 4 3 3 3
4 4 3 3 4 4
3 4 4 3 4 4
4 4 3 4 3 3
3 4 3 3 3 3
3 3 3 3 4 3
4 3 3 3 3' 3
T A M 428 IS-2223 IS-3390 IS-8171 IS-2232
73 60 62 98 62
3 4 3 3 3
5 3 5 5 3
3 5 4 4 5
3 4 4 3 3
3 3 3 3 3
3 4 3 3 3
4 3 3 3 3
IS-7254 IS-7322 IS-2276 CS-3541 IS-2225 BRANDES
2 '■
a. 1 = highly resistant and 5 = highly susceptible on a scale of 1 to 5. b. Leaf blight, grey leaf spot, anthracnose, zonate leaf spot, rust, rough leaf spot, and sooty stripe. c. Eight locations in India (Indore, Navsari, Kovilpatti, ICRISAT Center), Thailand (Khon Kaen), Niger (Seha), Nigeria (Samaru). and Upper Volta(FarakoBa). d. Mean number of days to 50% flowering.
45
Table 31. Sorghum cultivars stimulating nitrogenase activitya in the irrigated postrainy season 1978-79.
Cultivar IS-239I IS-1050 IS-3756 IS-2663 IS-15162 19/10b IS-2207 IS-2318 IS-2333
Origin S. Africa India Ethiopia Uganda Cameroun USA India Sudan Sudan
μg N fixed/ core per day 256 235 86 82 69 61 51 31 30
Active seasons 2 2 2 2 2 1 2 3 2
Max. activity in other seasons Total tested μg N/core per day 2 3 2 3 2 1 4 5 5
66 54 56 82 50 158 130 325
a. Plants were assayed during the grain filling stage 108 days after planting. b. Tested for first time.
N/core per day. Eight of these nine cultivars were found to be active in both seasons. Large increases in dry-matter production and nitrogen uptake were obtained for CSH-5 plants grown in vermiculite in pots, following inoculation with a crude enrichment culture obtained f r o m the roots of Napier bajra (Pennisetum americanum x P. purpureum). In 49 days, inoculated plants accumulated as much as 108 mg N/plant, without addition of any nitrogen fertilizer (Table 32). The response of sorghum CSH-6 seedlings to inoculation with Azospirillum lipoferum, A. brasilense, Azotobacter chroococcum, and Derxia spp was examined for plants grown in 25 x 200-mm test tubes with washed, sterilized vermiculite as the root medium. The tubes were inoculated at sowing and the plants were assayed f o r their nitrogenase activity 8 days later. The highest activity of 364 n m o l C 2 H 4 / plant per 24-hr incubation period was obtained w i t h plants inoculated with Azotobacter chroococcum. The activity in the uninoculated control plants was 1.2 n m o l C 2 H 4 / p l a n t per 24-hr i n cubation period. We are exploring whether this technique w i l l be useful for studying host cultivar-bacterial strain interactions in nitrogen fixation associated w i t h sorghum.
46
Looking Ahead Breeding. The promising sorghum varieties with good grain quality that we have identified will continue to be supplied to various national programs. Elite varieties and hybrids will be increasingly tested in India in collaboration with the A l l India Coordinated Sorghum I m provement Project. Search for nonrestorers has been successful, and a diverse array of seed parents or A lines w i l l be developed in the next few years. Interdisciplinary activities among breeders, physiologists, pathologists, and entomologists w i l l be intensified in order to evaluate breeding material against various stress factors such as drought, stalk rots, and insect pests. Having achieved success on techniques of rearing stem borer larvae and inducing artificial infestation, we plan to screen germplasm and breeding material for resistance to this major pest. The value of traits like glossiness and presence/ absence of trichomes in breeding for insect resistance w i l l be more critically examined. Breeding activities at I C R I S A T regional substations in India w i l l be expanded. Certain problems in breeding cannot be researched in
India (for example, Striga hermonthica and Busseola fusca); therefore major efforts on Striga are being shifted to Africa (Upper Volta). Identification and utilization of resistance to grain molds like Curvularia and Fusarium were rewarding, and our future efforts will be to combine resistance to other important molds like Phoma. Having established some procedures to evaluate food quality of breeding material, we will be giving more attention to this area of research, particularly in collaboration with scientists in Africa.
Entomology. Our screening efforts for shoot fly resistance w i l l concentrate increasingly on the material emanating f r o m the breeding programs in addition to any newly added material f r o m the germplasm collections. A t tempts to determine the chemical and physical bases for resistance to sorghum shoot fly w i l l be intensified in collaboration with the scientists at I C I P E , N a i r o b i . Studies on the fly larval movement, adult migration, and pupal diapause, if any, w i l l be carried out. Efforts w i l l be made to develop an effective artificial diet for the fly. The chemicals responsible for attraction in fish meal will be tested in collaboration with the M a x Planck Institute, West Germany. W o r k on chemicals responsible for host-plant resistance will be carried out in collaboration with COPR, L o n d o n , and I C I P E , N a i r o b i .
Biochemistry. Studies on the relationship of physicochemical and chapati characteristics of sorghum will be extended to more sorghum cultivars in order to test our initial findings. Efforts will be made to improve our taste-panel evaluation procedures.
To evaluate resistance, a special midgescreening area will be developed at Dharwar,
Table 32. Nitrogen balance as mg N/pot of sorghum CSH-5 grown in vermiculite in pots for 49 days.
Fertilizer N a (kg/ha) 0
20
120
Inoculated/ uninoculated Inoculated with Napier bajra root enrichment culture With isolate from Sorghum halepense With boiled composite Uninoculated Unplanted Inoculated with Napier bajra root enrichment culture With isolate from Sorghum halepense With boiled composite Uninoculated Unplanted Uninoculated
Initial N in vermiculite''
Final N in vermiculite mgN /pot
Total N in plant materialc
Overall N gain
7
180
369
541
10 7 6 0.5
158 113 68 45
187 152 99
335 258 161 44.5
60
23
140
103
63 60 59 54
-10 214 68 45
173 89 127
100 243 136 -8
323
233
248
158
a. N fertilizer addition as NH 4 SO 4 , calculated on a surface area basis. 20 kg N/ha = 53 mg N/pot, 120 kg N/ha = 318 mg N/pot. b. Includes initial N in vermiculite, fertilizer inoculum, and seed. c. For five plants per pot.
47
which is a midge-endemic area in South India. Subsequently, material emerging f r o m the breeding programs incorporating identified resistances w i l l be screened. M o r e information w i l l be obtained on the biology, carryover, host plants, and natural enemies of the midge fly. Detailed w o r k w i l l be carried out on the biology and ecology of the earhead bug complex. Attempts w i l l be made to develop screening techniques, which w i l l be utilized to screen material generated f r o m the breeding programs. Material emerging f r o m the screening programs f o r all major pests w i l l be put in pest nurseries in India and overseas. W o r k w i l l be carried out on the armyworm (Mythimna separata), shoot bug (Peregrinus maidis), and headworm complex. Studies on pest biology, carryover, population dynamics, host-parasite relationships, and evaluation of attractants and pheromones w i l l be intensified.
Pathology. O u r efforts in sorghum pathology will include: (1) identification and utilization of lines with resistance to Phoma; (2) screening new germplasm collections to identify diversified source material resistant to grain molds;
downy mildew; and leaf, stalk, and root diseases; (3) analysis of molded grain for mycotoxins; (4) characterization of various components in sorghum grain deterioration; (5) identification and utilization of source material consistently less susceptible to charcoal rot, leaf diseases, and downy mildew; (6) investigations on the development of a possible screening technique for charcoal rot resistance in the seedling; (7) investigations on the role of various stress factors in the development of charcoal r o t ; (8) identification of stable sources of resistance to ergot; (9) identification of more " h o t spot" locations for screening leaf diseases, charcoal rot, and sorghum downy mildew under natural infection conditions; and (10) improvements in screening techniques for resistance to leaf diseases and charcoal rot. Microbiology. Nitrogen fixation associated with sorghum roots will be studied in nitrogen balance experiments in pots, in lysimeters, and in the field, using isotopic 1 5 N . The response of sorghum to inoculation with nitrogen-fixing bacteria will be characterized, using bacterial cultures obtained f r o m plants in traditional sorghum-growing areas in the SAT.
Publications Journal Articles J.C., and SESHU REDDY, K.V. 1976. Sorghum shoot fly (Atherigona soccata host) grasses. SemiArid Cereals 2:8-9. Available from ICRISAT.
DAVIES,
NESBITT, B.F., BEEVOR, P.S., H A L L , D.R., LESTER, R., DAVIES, J.C., and SESHU REDDY, K.V., 1979. Com-
ponents of the sex pheromone of the female spotted stalk borer, Chib partellus (Swinhoe) (Lepidoptera: Pyralidae): identification and preliminary field trials. Journal of Chemical Ecology 5:153-163.
48
K.V. 1977. Identification of male-sterile gene in sorghum. Current Science 46:155. RAMAIAH, K.V., and CHIDLEY, V.L. 1977. Preliminary results of the Striga resistance breeding program at ICRISAT. Semi-Arid Cereals 3:7-8. Available from ICRISAT. RAMAIAH,
SESHU REDDY, K.V., and DAVIES,
J.C.
1978. A new
medium for mass rearing of the sorghum stem borer, Chib partellus Swinhoe (Lepidoptera: Pyralidae) and its use in resistance screening. Indian Journal of Plant Protection 6(l):48-55.
S.V.R., and M A I T I , R.K. 1978. Some observations on the root system of some tropical dicotyledonous weeds. Indian Journal of Weed Science 10(l):4-48.
SHETTY,
SKINNER, J.D., DAVIES, J.C, and SESHU REDDY, K.V.
1979. A note on the discovery of the male of Acritochaeta distincta M A L L . (Diptera: Muscidae). Journal of Bombay Natural History' Society 75(1) :240- 241.
Conference Papers ANDREWS,
D.J.,
VERMA,
B.N.,
and
HARE,
B.W.
1977. Methods of population improvement in pearl millet and sorghum. Second FAO/SIDA Seminar on Field Food Crops in Africa and the Near East. FAO/SIDA, 18 Sept 1977, Lahore, Pakistan. CASTOR,
L.L.,
FREDERIKSEN,
R.A.,
RAO,
K.N.,
and
R.J. 1979. Fungal antagonism among four sorghum grain mold fungi: importance in screening programs. Ninth International Congress of Plant Protection, 5-11 Aug 1979, Washington, D.C., USA. DANGE, S.R.S., and WILLIAMS, R.J. 1978. The ICR1SAT SDM program. International Workshop on Sorghum Diseases. ICRISAT, 11-15 Dec 1978, Hyderabad, India. DAVIES, J.C, and SESHU REDDY, K.V. 1977. Insect pests of sorghum and pearl millet and assessment of insect numbers and losses. Page 12 in Proceedings, All India Workshop on Assessment of Crop Losses due to Pests and Diseases, 19-30 Sept 1977, Bangalore, India. DAVIES, J.C, and SESHU REDDY, K.V. 1978. Sorghum entomology program at ICRISAT. Page 4 in Proceedings, All India Coordinated Sorghum Improvement Project Workshop. ICAR, 17-19 Apr 1978, Dharwar, India. DAVIES, J.C, and SESHU REDDY, K.V. 1979. Species of shoot flies bred from sorghum at Patancheru, Andhra Pradesh. Page 6 in Proceedings, Golden Jubilee Celebration of the Sorghum Research Station, Parbhani, 24-25 Feb 1979, Parbhani, India. DOGGETT, H. 1977. Keynote address. International Sorghum Workshop. ICRISAT, 6-13 Mar 1977, Hyderabad, India. JAMBUNATHAN, R. 1977. Evaluation of nutritional quality of cereals-screening methodology. Pages 186-199 in Proceedings, Symposium on Genetics Applied to Human Needs. Government of India, WILLIAMS,
Department of Atomic Energy, 10-11 Jan 1977, Bombay, India. JAMBUNATHAN, R. 1978. Improvement of the nutritional quality of sorghum and pearl millet. Eleventh International Congress of Nutrition, 27 Aug1 Sept 1978, Rio de Janeiro, Brazil. JAMBUNATHAN, R., and SINGH, U. 1977. Nutritional
quality of cereals and pulses: rapid screening methods for the evaluation of protein quality. Page 49 in Proceedings, Forty-sixth Annual Meeting of the Society of Biological Chemists, 22-25 Sept 1977, Madras, India. M A I T I , R.K. 1976. Growth and development of panicles and grains of some sorghum hybrids and their parents. Pages 81-112 in Proceedings, Advances in Plant Reproductive Physiology, ed. C.P. Malik. First International Symposium on Physiology of Sexual Reproduction in Flowering Plants, 23-24 Dec 1976, Ludhiana, India. New Delhi: Kalyani Publishers. MAITI,
R.K.,
RAJU, P.S., and BIDINGER, F.R.
1979.
Studies on germinability and some aspects of preharvest and postharvest physiology of grain sorghum. National Seminar on Physiological Basis of Crop Productivity and Harvesting Solar Energy in Relation to Agricultural Development, 19-21 Mar 1979, Aligarh Muslim University, Aligarh, U.P., India. MURTY,
D.S., PATIL,
H.D., and HOUSE,
L.R.
1979.
Breeding for sorghum food quality at ICRISAT. Pages 38-39 in Proceedings, Eleventh Biennial Sorghum Research and Utilization Conference. Wichita, Kansas, USA. MURTY,
D.S.,
RAO,
K.N.,
and
HOUSE,
L.R.
1978.
Breeding for grain-mold resistant sorghums at ICRISAT. International Workshop on Sorghum Diseases. ICRISAT, 11-15 Dec 1978, Hyderabad, India. RAO, K.N., and WILLIAMS, R.J. 1978 Charcoal rot
resistance screening at ICRISAT, Rabi 1977-1978 (Research note), All India Sorghum Workshop (All India Coordinated Sorghum Improvement Project-AICSIP), 17-19 Apr 1978, Dharwar, India. RAO, K.N., and WILLIAMS, R J . 1978. Screening for
sorghum grain mold resistance at ICRISAT. International Workshop on Sorghum Diseases. ICRISAT, 11 -15 Dec 1978. Hyderabad, India. . SEETHARAMA,N.,SIVAKUMAR, M.V.K., SARDAR SINGH, and BIDINGER, F.R. 1979. Sorghum productivity under receding soil moisture in Deccan plateau. Presented in the Poster Session during the International Symposium on Biological Applications of
49
Solar Energy, 1-5 Dec 1978, Madurai, India. SESHU REDDY, K.V., and DAVIES, J.C.
1978. The role
of the entomology program with reference to the breeding of pest-resistant cultivars of sorghum at ICRISAT. Page 8 in Proceedings, National Symposium on Strategies of Insect Pest Control through Integrated Methods. Indian Agricultural Research Institute (IARI), 16-17 Aug 1978, New Delhi, India. SESHU REDDY, K.V., and DAVIES, J.C. 1978. The use
of attractant traps for the assessment of sorghum shoot fly Atherigona soccata Rondani (Muscidae: Diptera) populations. Page 6 in Proceeding, Oriental Entomology Mini Workshop on Population Ecology in Relation to Insects of Economic Importance, 18-20 Jan 1978, Bangalore, India. VON O P E N , M., and JAMBUNATHAN, R. 1978. Con-
sumer preferences for cryptic and evident quality characters of sorghum and millet. In Proceedings, Diamond Jubilee Scientific Session of the National Institute of Nutrition, 23-27 Oct 1978, Hyderabad, India. WILLIAMS, R.J. 1978. The International Sorghum Downy Mildew Nursery. International Workshop on Sorghum Diseases. ICRISAT, 11-15 Dec 1978. Hyderabad, India. WILLIAMS, R.J., and RAO, K.N. 1978. A review of sorghum grain molds. International Workshop on Sorghum Diseases. ICRISAT, 11-15 Dec 1978, Hyderabad, India.
30
Contents Breeding Source Material Composite Breeding Intrapopulation Improvement Interpopulation Improvement Comparison of Population Improvement Methods Variety Crosses and Synthetics Hybrids Development and Improvement of Seed Parents Conventional backcrossing Exploitation of residual variation Induction of disease resistance International Trials Distribution of Seed Material
Biochemistry Protein and Lysine Study F o o d Product Study Sugar Content Study
Physiology Evaluating Genotypes under Drought Stress Factors affecting yield in stress treatments M e t h o d of evaluation G r a i n Y i e l d , G r a i n Number, and Kernel Weight Variation in grain number and kernel weight G r a i n number and preflowering growth Considerations f o r yield improvement
52
53 53 54 54 55 56 57 57 59 59 59 59 60 63 63 63 65 65 66 66 66 67 68
Leaf-Water Potential in Pearl Millet Diurnal changes Control of leaf-water potential
Entomology
71
Pathology
71 71
D o w n y Mildew Resistance Screening at I C R I S A T Center Multilocational Testing The 1978 P r e - I P M D M N The 1978 I P M D M N Alternative Control Ergot Resistance Screening at I C R I S A T Center The basic technique Initial screening Advanced screening Multilocational Testing Alternative C o n t r o l C o n t r o l of ergot through pollen management Smut Resistance Screening Multilocational Testing Rust Initial Resistance Screening Multilocational Testing
71 72 72 72 72 74 74 74 74 75 75 76 76 77 77 77 79 79 79
Microbiology
79
Looking Ahead
81
Publications
82
68 68 68
69 69 70
PEARL M I L L E T
The basic objective of the pearl millet improvement program is to develop and disseminate technology that will enable consistently higher levels of on-farm pearl millet yields than at present. The technology includes techniques, breeding procedures, and improved genotypes having stress resistances and high-yield potential. This report is structured by discipline, but as in other I C R I S A T crop improvement programs, there is considerable interdisciplinary interaction in project formulation, management, and execution.
Breeding The primary aims of the breeding activities are the development and distribution of novel and improved genotypes capable of producing high, stable yield, and possessing good grain quality and resistance to major diseases and other stress factors. To achieve these aims the program emphasizes close integration of activities at I C R I S A T Center and multilocational testing of breeding material in India and West Africa, including testing in downy mildew nurseries. Recurrent selection in composite populations and variety-cross approaches are emphasized equally in generating hybrids, synthetics, experimental varieties, and inbreds, as well as an array of breeding lines to be distributed to cooperating breeders in various countries.
Source Material Inflow of new variability is essential to continuous progress in a crop improvement program. The basic source material is the germplasm collection, which contains a rich diversity
of genotypes (see Genetic Resources U n i t section of this report). In our source material project, selected germplasm accessions, as well as source populations developed by breeders outside I C R I S A T , are maintained and utilized. These germplasm accessions have been crossed to adapted lines and progenies have been selected for use in the hybrid as well as the varietycross program. Of the nine source populations in this project, eight originated in West Africa, and four contain appreciable amounts of photosensitivity. These populations are being improved by progeny evaluation, and good progenies have been crossed to male-sterile lines to identify potential pollinators and seed parents for hybrids. Crosses have also been made to elite material to move desirable characteristics into more agronomically advanced backgrounds. In the 1978 rainy season, S 2 progenies of three West African dwarf populations (3/4 Heine K h e r i , 3/4 Ex Bornu, and Saria Synthetic) were grown at Bhavanisagar in South India ( U N ) . Mean yields were 3418 kg/ha f o r 3/4 Heine Kheri progenies, 4163 kg/ha f o r Ex Bornu progenies, and 3689 kg/ha f o r Saria Synthetic progenies. Eight progenies f r o m Ex B o r n u , five f r o m 3/4 Heine K h e r i , and five f r o m Saria Synthetic were chosen to develop experimental varieties, and selection differentials for grain yields were about 20%. Recombinations of the selected progenies to f o r m experimental varieties were done in summer 1979 in the I C R I S A T Center downy mildew nursery. Several good progenies with a wide range of diversity were generated f r o m source populations and source x adapted crosses. An F 3 progeny nursery (837 lines), derived f r o m crosses involving West A f r i c a n d w a r f populations (S 2 progenies) and established I n d i a n inbreds, was grown at I C R I S A T Center in the
53
rainy season of 1978. About 450 individual plants from 17 different crosses were selected to enter the 1979 Uniform Progeny Nursery and for developing experimental varieties. A large number of test crosses were also made using these progenies. Trials in 1978 identified several potentially useful products from this project. The hybrid ICH-241 (5141A x Serere 38-142), of which the pollinator is derived from the Working Collection, and two synthetics derived from source populations (ICMS-7819 and ICMS7820) performed well in advanced trials. In the Source Material Hybrid Trial, three new hybrids were identified for testing in the Advanced Hybrid Trial of 1979. These were 5141A x 7173 (2880 kg/ha), 5141A x 7177 (2819 kg/ha), and 5141A x S38-36 (2794 kg/ha). In this trial, the check hybrid BJ-104 yielded 2236 kg/ha. Source material progenies proved to be a valuable source for resistances to downy mildew and smut. Six progenies, all originating from Ex Bornu, were moved from the 1978 Pre-International Pearl Millet Downy Mildew Nursery (Pre-IPMDMN) into the 1979 I P M D M N . Three progenies from Ex Bornu (EB 137-1-1, EB 74-3, and EB 24-1) were smut-free in the 1978 advanced smut screening trials.
Composite Breeding Intrapopulation Improvement The number of composites under intrapopulation improvement was reduced from 13 to 11 in 1978 by merging certain composites with similar phenotypes. Early Composite was merged with Dwarf Composite to form D 1 Composite; Late Composite and Nigerian Composite were merged to form the new Late Composite; and D2 Composite was developed by merging GAM-75, GAM-73, and a few other dwarf D 2 lines. One new composite, Elite Composite, was formed by combining high-yielding, downy mildew resistant, and agronomically superior lines selected from all composites
54
under recurrent selection at ICRISAT in 1977. By the beginning of the 1979 postrainy season we had completed four cycles of selection in one composite, three cycles in three composites, two cycles in three composites, and one cycle in one composite. The first cycle of S2 progeny selection was started on the three new composites derived from composite merging. Selection within individual composites was based on performance of 200 to 300 progenies, replicated twice and tested in three to five environments, with an additional replication in downy mildew nursery at ICRISAT Center for within-line selection and seed multiplication. Composite progenies have also been tested in West and East Africa since 1977 with the assistance of ICRISAT breeders at those locations. From the composite progeny trials conducted in 1978, 22 to 40 progenies per composite were selected for recombination, and the average selection differential for grain yield was 23.6%. Recombination was effected in the downy mildew nursery using only disease-free plants. Based on visual score, disease rating, and grain yield, four to eight progenies from each composite were selected for developing six across-location and 15 location-specific experimental varieties. In merging the Early Composite and the Dwarf Composite, line-to-line crosses were made and evaluated along with their parents. Based on the performance of the crosses and the general combining ability of their parents, three experimental varieties were developed from six crosses. To assess the genetic gain from selection in these composites, comparisons of C 0 , C1, and C2 bulks were made in six composites in five environments in India and West Africa. Based on Indian locations where composite progenies were tested during the process of recurrent selection, an average gain in seed yield of 4.2% per year was recorded, although the differences from cycle to cycle were not statistically significant, except for Medium Composite, which showed a 12.5% gain in seed yield per year. Most of the composites improved in India did not show any improvement in West Africa. Selection was effective in reducing plant height and
increasing the level of downy mildew resistance. Progeny testing in the more advanced cycle in these composites showed no reduction in variability for yield, indicating that the selection methods employed had not rapidly diminished the potential for improvement. The practical products f r o m the composites are experimental varieties and individual best progenies generated in each cycle of selection. The advanced cycle bulks of composites are not intended for release (except to other breeders on request). Composite products tested at several locations in India and Africa in 1978 included 45 experimental varieties and 79 best progenies. The 1978 Experimental Variety Trial included, for the first time, experimental varieties derived by recombining progenies selected at I C R I S A T ' s West African locations in 1977. Thirty-four experimental varieties had grain yields equivalent to the commercial hybrid check BJ-104 (2580 kg/ha), and all were superior in downy mildew resistance. One experimental variety, WC-B77, was significantly better for grain yield (3110 kg/ha) than BJ-104. Three experimental varieties, WC-B77, 1VS-P77, and M C - K 7 7 , were selected for further testing; the first two were also entered in the A l l India Coordinated Millet Improvement Project ( A 1 C M I P ) trials to be conducted in 1979. A l l five I C R I S A T experimental varieties in the 1978 A I C M I P trials did well. A m o n g those entries tested for 3 years, WC-C75 was the highest yielder, with a mean yield of 1731 kg/ha; this was equal to 94% of the yield of the commercial hybrid BJ-104. This variety will be entered in minikit trials in 1979 and will be included as the check entry in the population trials. The remaining entries (IVS-A75 and MC-C75 in Advanced Population T r i a l , and SSC-H76 and MC-P77 in Initial Population Trial) were the best-yielding entries in their respective trials. Of the 79 individual progenies tested, 62 gave the same yield level as the hybrid check BJ104 (2413 kg/ha), and the majority recorded a lower incidence of downy mildew. One progeny, IVS-7190, gave a significantly higher
yield (3158 kg/ha) than BJ-104. Ten progenies were selected for advanced testing in the 1979 Elite Varieties T r i a l . A trial to assess inbreeding depression in experimental varieties and in individual progenies by comparing Syn 0, Syn 1, and Syn 2 indicated a slight but nonsignificant increase in grain yield f r o m generation to generation. However, there was a significant yield loss in two out of four experimental varieties and one out of eight individual progenies. It seems that the varieties need to be considered individually; some yield losses may occur in certain varieties, but the majority w i l l maintain the same yield levels in successive generations. A dwarf "side-car" program was devised to convert seven tall (normal) composites w i t h plant height ranging f r o m 170 to 230 cm, into dwarf d 2 versions by backcrossing, using largely G A M - 7 3 and G A M - 7 5 (which measured below 140 cm) as the d 2 gene donors. The third and final backcross was completed in the rainy season of 1978, and the F 2 populations were generated in the 1979 summer season. Twentyfive promising dwarf F 3 progenies, derived f r o m the first backcross generation, were selected for entering in the U n i f o r m Progeny Nursery and were used in developing six d 2 dwarf synthetics.
Interpopularion Improvement One cycle of reciprocal full-sib recurrent selection was completed in the 1R/1B composite pair, and the second selection cycle commenced. Based on the results f r o m the first cycle of selection, two experimental varieties of different heights (165 cm and 182 cm) were developed, and 22 test-cross hybrids, some of which produced higher grain yield than the commercial hybrid BJ-104 by as much as 3 1 % , were selected f o r further evaluation in the Initial H y b r i d T r i a l The t h i r d and final round of random mating was completed in another complementary pair of populations—2R and 2B, and S 1 progenies and test-cross hybrids were generated f o r the evaluation of agronomic traits and restorer reactions.
55
ICRISAT plant breeder examines a new pearl millet hybrid generated in the interpopulation improvement program.
Based on a diallel study of 16 I C R I S A T composites, two additional complementary composite pairs ( G A M - 7 5 x 3/4 Ex Bornu and Serere Composite 2 x Nigerian Composite) were identified for reciprocal recurrent selection. Following the reciprocal full-sib method of recurrent selection, G A M - 7 5 x 3/4 Ex Bornu entered the second cycle of selection, and two experimental varieties were generated from selected progenies of 3/4 Ex Bornu. The Serere Composite 2 x Nigerian Composite pair is being improved by the reciprocal inbred tester method. These populations have mixtures of both restorer and maintainer plants, and the possibility of converting one population into a
56
restorer type and the other into a maintainer type is being examined. Comparison of Population Improvement Methods In order to provide pearl millet breeders with information on the relative values of different methods of recurrent selection, a 7-year study was initiated in 1976 to compare four principal methods of recurrent selection: gridded mass selection (GMS), recurrent restricted phenotypic selection (RRPS), full-sib progeny selection (FSPS), and S 2 progeny selection (S 2 PS). The W o r l d Composite was chosen for this study, and the same selection intensity (10%)
and selection criteria were used in all methods. At the end of 1978, the S 2 PS was in the second cycle and the other methods were in the fourth cycle of selection. Random-mated bulks, selfed bulks, and test crosses (using four testers) produced from the individual methods of selection w i l l be compared.
Variety Crosses and Synthetics In the variety-cross project, new inbreds and partial inbreds are generated each year by crossing two or more complementary lines, mainly Indian x African, followed by pedigree selection for two or three generations. These lines are evaluated for performance per se, for use in making synthetics, and for potential as hybrid parents. To provide the national programs with new sources of clear-cut variability, selected lines w i t h a range of diversity are distributed to cooperating breeders annually in the f o r m of U n i f o r m Progeny Nurseries. In the 1978 rainy season, the F 1 s and F 2 s grown at I C R I S A T Center, Hissar, and Bhavanisagar included 2000 variety-cross F 1 S and 450 F 2 populations. F,s with obvious defects were rejected and those remaining were selfed to produce F 2 populations. I n d i v i dual plant selections were made f r o m the F 2 populations for further evaluation as F 3 lines. A variety-cross progeny nursery of about 2000 entries (F 3 s, F 4 s, and F 5 s) was grown at I C R I S A T Center, and selections were made for further advance and evaluation. The F 4 (200 entries) and F 5 (100 entries) U n i f o r m Progeny Nurseries were sent to 12 locations in six countries and eight locations in three countries, respectively. Several lines were selected for use in national breeding programs. Synthetics were formed by combining the individual sets of lines selected on the basis of performance per se and/or combining ability. They were first tested in the Initial Synthetics Trial at a limited number of locations ( I C R I S A T Center i n , low and high fertility, Hissar, and/or Bhavanisagar) and in the
I C R I S A T Center downy mildew nursery. Promising entries were moved to the Advanced Synthetics T r i a l for testing at a larger number of locations, including some in Africa. The 1978 advanced Pearl Millet Synthetics Trial (PMST-1), consisting of 22 synthetics and three checks, was grown at four locations in India and two locations in Africa. Mean grain yields and downy mildew incidence of selected entries are shown in Table 1. I C M S 7806 was the top-yielding entry at Indian and African locations, and also had a low incidence of downy mildew.
Hybrids Inbreds or partial inbreds generated f r o m the source material, population improvement, and variety-cross projects are channeled into hybrid development and testing activities. They are crossed to three male-sterile lines (5054A, 5141 A, and 111A), and the resulting test-cross hybrids are initially evaluated in unreplicated trials at I C R I S A T Center. Selected hybrids are entered in the initial replicated hybrid trial at several locations, including the I C R I S A T Center downy mildew nursery. Promising entries with downy mildew resistance and satisfactory agronomic characters are then entered in the advanced hybrid trial at a larger number of locations in an international cooperative trial. The best hybrids f r o m the advanced trial are more intensively evaluated in the International Pearl Millet Adaptation T r i a l ( I P M A T ) and in national testing programs. In the 1978 Pearl Millet H y b r i d Trial ( P M H T - 1 ) , 23 I C R I S A T hybrids were tested at three locations in India and two locations in West A f r i c a along with two commercial hybrids included as checks. The four top-yielding hybrids at Indian locations were ICH-105, I C H - 2 4 1 , ICH-220, and ICH-206. A l l produced higher grain yields and had lower downy mildew incidence than the hybrid checks BJ-104 and PHB-14 (Table 2). At the African locations, ICH-162, I C H - 2 1 1 , ICH-165, and ICH-238 were the best-yielding entries; and ICH-162,
57
Table 1. Grain yields and downy mildew incidence of selected entries in PMST-1,1978. DM incidence (%)
Mean grain yield (kg/ha)
Tarna (Niger)
Bambey (Senegal)
0 4 4 0 1
1 2 3 3 3
4 1 2 1 1
2485 2580 1848 2439
0 22 12 1
1 6 6 3
2 1 14 1
2400 213
NA
NA
NA
Four Indian locationsa
Two African locationsb
All locations
ICMS-7806 ICMS-7703 ICMS-7816 ICMS-7818 ICMS-7805
3094 2928 2893 2925 2812
2355 2039 2079 1977 2195
2847 2631 2622 2609 2606
ICMS-7819 BJ-104 (Hybrid check) PSB-3 (Variety check) WC-C75 (Variety check)
2707 3059 2197 2752
2042 1621 1056 1814
2705 234
1788 408
Entry
Mean (25 entries) LSD (0.05)
ICRISAT Center
a. ICRISAT Center high and low fertility, Hissar, and Bhavanisagar. b. Tarna (Niger) and Bambey (Senegal). NA = Not averaged.
Table 2. Grain yields and downy mildew incidence of selected entries in PMHT-1,1978. Mean grain yield (kg/ha)
Entry
Pedigree
Three Two Indian African All locationsa locations* locations
DM incidence (%) ICRISAT Center
Tarna Kano (Niger) (Nigeria)
ICH-105 ICH-162 ICH-206 ICH-238 ICH-165
5054A x B282 111A x 700429-14 5141A x NW 15-18 111A x (T 166-2 x 700594-10-3-4) (7651) 111A x SC 14(M)
3115 2506 2776 2557 2501
2384 2981 2566 2716 2734
2822 2696 2692 2621 2594
0 0 3 0 2
11 2 10 8 3
23 5 24 9 7
ICH-211 ICH-241 ICH-220 BJ-104' PHB-14c
5141A x NC-SN 38-1 5141A x S-38-142 5054A x (SD2 x E x B-2) (D-1088)P-1 5141A x J104
2329 3060 2924 2667 2252
2919 1560 1579 1725 1769
2565 2460 2271 2290 2059
0 4 2 13 5
2 5 17 8 1
8 26 32 21 8
2595 382
2313 475
2482 262
NA
NA
NA
111A X PIB-228
Mean (25 entries) LSD (0.05) a. ICRISAT Center high and low fertility, and Hissar. b. Tarna (Niger) and Bambey (Senegai). c. Check entry. NA = Not averaged.
58
ICH-238, ICH-165, and ICH-211 had low levels of downy mildew. Some of these hybrids were not sufficiently u n i f o r m and need reselection in the pollen parent before retesting. In three other initial hybrid trials, 35 hybrids were identified for retesting in 1979. Pollinators of these hybrids included inbred varieties as well as population progenies.
Development and Improvement of Seed Parents Only a few male-sterile lines have been developed ; of these, some have major defects such as unstable sterility and are not utilized commercially. Progress in hybrid breeding has been restricted to the improvement of male parents, which combined well w i t h these male-sterile lines. To widen the scope of generating better hybrids, we have been involved in breeding new male-sterile lines, including male-sterile lines suitable for African conditions. Three approaches are being used to develop and improve seed parents for hybrid production: Conventional backcrossing. Sterile cytoplasm of the A 1 system is being introduced into maintainer lines, using the conventional backcrossing technique. These lines were derived f r o m variety crosses and crosses involving B-lines (tested for maintenance ability in F 3 generation) and source material. D u r i n g the 1978 postrainy season, four inbred lines (Ex Bornu 1 8 - 1 , Casady D w a r f 5 - 1 , 3/4 Heine K h e r i 207, and Casady D w a r f 67-1), and corresponding sterile hybrids, were planted for the third backcross. Plant-to-plant crosses of these inbreds were found to be sterile in both rainy and postrainy seasons. The fourth backcross will be attempted in the rainy season of 1979 in the disease nursery, and also initial test crosses w i l l be made to assess the combining ability using a set of standard restorers. Exploitation of residual variation. Considerable residual genetic variability occurs in the existing male-sterile lines and their maintainer counterparts, and in morphological characters,
seed set, downy mildew resistance, and the frequency of pollen shedders in the A-line. Variability for these undesirable characters is being minimized in four male-sterile lines and their corresponding maintainers ( 1 2 6 D 2 , 6 7 , 6 6 , and Serere 10L) by making a large number of plant-to-plant crosses and subsequent testing in the disease nursery. The defects include fertile sectors in 67A, high frequency of pollen shedders in 66A, poor seed set and grain color in 126D 2 A, and a high proportion of fertiles and segregation for bristling in Serere 10LA. Individual plantto-plant pairs w i t h improvements of their respective defects were selected in 67, 66, and 126D 2 . However, we failed to identify a good A and B pair in Serere 10L, though we grew more than 600 plant-to-plant crosses. Induction of disease resistance. One major factor limiting the use of male-sterile lines is their susceptibility to downy mildew ( D M ) . An example is the male-sterile line 2 3 D 2 A , a dwarf and good combiner developed in USA. This line is highly susceptible to DM b o t h in India and Africa. To induce downy mildew resistance, seed of 2 3 D 2 B was treated w i t h gamma rays (30 kr), and f r o m the M 2 generation onwards, disease-free plants (in the I C R I S A T Center downy mildew nursery) were selected and backcrossed to the A line, using pedigree selection. In the 1978 rainy season, the fifth backcross was made and three pairs were selected for multiplication in 1979, based on DM reaction and morphological uniformity. Initial test crosses made w i t h selected dwarf inbreds were evaluated in summer 1979. Results are presented in Table 3. The improved 2 3 D 2 progenies took between 48 and 66 days to flower, and were resistant to DM but highly susceptible to smut. To incorporate earliness and smut resistance, crosses were made in the postrainy season of 1978 using 2 3 D B (received f r o m D r . Glenn W. B u r t o n , U S A ) as the source of earliness and smut-resistant lines EB-24-1, EB-74-3, EB-1371-1, WC-FS-148, and SSC-FS-252. The F 2 populations w i l l be grown in 1980 to screen for dwarfs w i t h low smut susceptibility and earliness.
59
A highly DM-resistant version (right) has been developed from a highly DM-susceptible line, 23D2B (left) through irradiation-induced mutation, followed by selection in the DM-screening nursery at ICRISAT Center.
International Trials In 1978, the fourth International Pearl Millet Adaptation Trial ( I P M A T - 4 ) comprising 20 entries, contributed by cooperators and I C R I S A T , was sent to 51 locations in 20 countries. The entries included hybrids, synthetics, experimental varieties, population bulks, and a local check. Data were received from 37 locations in 13 countries ranging from 28 40'S to 30"41' N, of which 36 locations reported data on grain yield. The highest location mean grain yield was recorded at Serere, in Uganda (4213 kg/ha) and the lowest (227 kg/ha) at Anantapur in India. The mean grain yield over all locations was 1992 kg/ha. The highest-yielding entry over all locations was the hybrid MBH-110, con-
60
tributed by the Maharashtra Hybrid Seed Company, India, and the lowest was Ex Bornu Bulk. The top grain yields at individual locations ranged from 659 kg/ha (PHB-47 at Anantapur) to 5061 kg/ha (ICMS-7703 at Serere). Mean yields of the test entries were higher than the yields of the local checks at 18 locations. The mean grain yields of each entry for all locations, Indian locations, and African locations are presented in Table 4. In Africa, six of the seven top entries were bred using either totally or partly African germplasm (exception: GHB-27). Rank correlation between entry mean yields for all locations and for Indian locations, and for all locations and for African locations were positive and significant (0.83 and 0.74, respectively). However, the correlation for rankings
Table 3. Performance of some selected dwarf test crosses of pearl millet derived using improved 23D2 A, summer 1979.a Field Code
Plant height (cm)
52 55 55 52 50 50 54
130 140 148 145 125 150 145
2866 3333 3600 3333 3466 3800 4000
4.6 6.7 6.2 6.5 6.0 5.3 6.3
Mean (of 29 selected test crosses) Range: Minimum Maximum
52 49 55
133 110 150
2972 1800 4000
5.7 3.7 7.6
GHB 1399b' (dwarf hybrid check) BK 560c( commercial hybrid check) PHB-14c (commercial hybrid check)
48 41 48
117 145 163
2260 3222 3572
321 336 339 343 353 391 394
23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x 23D2A x F4(PIB 228 x
3/4 HK-119-35) 3/4 HK-119-35)P1 3/4 HK-119-35)P3 3/4 HK-119-35)PC 3/4 HK-119-74)P5 3/4 HK-113-4)PC 3/4 HK-113-4)P2
Grain yield (kg/ha)
1000-grain weight (g)
Days to 50% bloom
Pedigree
a. Planted 12January 1979, harvested 13 April 1979. Fertilizer dose: 120 kg N, 60 kg P/ha; plant population 125 000 plants/ha. b. Mean of ten observations. c. Mean of three observations.
of entry means at Indian locations and at African locations was not significant. This nonsignificance was apparently due to the contrasting performances of entries M B H - 1 1 0 , ICH-105, and BJ-104, which are adapted to India but are highly susceptible to downy mildew in West Africa. The downy mildew incidences were much more severe on several entries in certain West African locations than in India, and some entries showed distinct differential reactions among West African locations. Hybrids ICH-118 and ICH-165 had relatively stable levels of downy mildew resistance across locations. Several other multilocational trials of composite progenies and products, inbreds, synthetics, and hybrids were also grown by cooperators in India and other countries. Distribution of these trials is shown in Table 5. In 1978, 19 I C R I S A T entries were tested in the A l l India Coordinated M i l l e t Improvement Project ( A I C M I P ) multilocational trials. T w o new hybrids (ICH-154 and ICH-165) were in the Initial Pearl M i l l e t H y b r i d T r i a l , and the
hybrid ICH-105 was retained in the Advanced H y b r i d Trial. T w o new experimental varieties (SSC-H76 and MC-P76) and one synthetic (ICMS-7703) were accepted to the Initial Pearl M i l l e t Population T r i a l , and three experimental varieties (WC-C75, IVS-A75, and MC-C75) were in the Advanced Population T r i a l . Ten elite restorers were contributed to the parental trial. H y b r i d ICH-154 gave higher yield (1993 kg/ha) than the mean yield of the Initial H y b r i d T r i a l (1950 kg/ha at 28 locations) and was promoted for advanced testing in 1979. A l l experimental varieties and synthetics did well in their respective trials. SSC-H76 and I C M S 7703 ranked first and second among the test entries in the Initial Population T r i a l , w i t h yields of 1952 kg/ha and 1932 kg/ha, respectively, compared w i t h the trial mean of 1744 kg/ha over 21 locations. Experimental varieties W C C75 (2073 kg/ha) and IVS-A75 (2008 kg/ha) were the top-yielding varieties in the Advanced Population T r i a l (trial mean over 33 locations was 1945 kg/ha). A m o n g the varieties that have been tested for 3 years, WC-C75 ranked first
61
Table 3. Performance of some selected dwarf test crosses of pearl millet derived using improved 23D2 A, summer 1979.a Field Code
Plant height (cm)
52 55 55 52 50 50 54
130 140 148 145 125 150 145
2866 3333 3600 3333 3466 3800 4000
4.6 6.7 6.2 6.5 6.0 5.3 6.3
Mean (of 29 selected test crosses) Range: Minimum Maximum
52 49 55
133 110 150
2972 1800 4000
5.7 3.7 7.6
GHB 1399b (dwarf hybrid check) BK 560c( commercial hybrid check) PHB-14c (commercial hybrid check)
48 41 48
117 145 163
2260 3222 3572
321 336 339 343 353 391 394
23D2A x F4(PIB 228 x 3/4 HK-119-35) 23D2A x F4(PIB 228 x 3/4 HK-119-35)P1 23D2A x F4(PIB 228 x 3/4 HK-119-35)P3 23D2A x F4(PIB 228 x 3/4 HK-119-35)PC 23D2A x F4(PIB 228 x 3/4 HK-119-74)P5 23D2A x F4(PIB 228 x 3/4 HK-113-4)PC 23D2A x F4(PIB 228 x 3/4 HK-113-4)P2
Grain yield (kg/ha)
1000-grain weight (g)
Days to 50% bloom
Pedigree
a. Planted 12January 1979, harvested 13 April 1979. Fertilizer dose: 120 kg N, 60 kg P/ha; plant population 125 000 plants/ha. b. Mean of ten observations. c. Mean of three observations.
of entry means at Indian locations and at African locations was not significant. This nonsignificance was apparently due to the contrasting performances of entries M B H - 1 1 0 , ICH-105, and BJ-104, which are adapted to India but are highly susceptible to downy mildew in West Africa. The downy mildew incidences were much more severe on several entries in certain West African locations than in India, and some entries showed distinct differential reactions among West African locations. Hybrids ICH-118 and ICH-165 had relatively stable levels of downy mildew resistance across locations. Several other multilocational trials of composite progenies and products, inbreds, synthetics, and hybrids were also grown by cooperators in India and other countries. Distribution of these trials is shown in Table 5. In 1978, 19 I C R I S A T entries were tested in the A l l India Coordinated M i l l e t Improvement Project ( A I C M I P ) multilocational trials. T w o new hybrids (ICH-154 and ICH-165) were in the Initial Pearl M i l l e t H y b r i d T r i a l , and the
hybrid ICH-105 was retained in the Advanced H y b r i d Trial. T w o new experimental varieties (SSC-H76 and MC-P76) and one synthetic (ICMS-7703) were accepted to the Initial Pearl M i l l e t Population T r i a l , and three experimental varieties (WC-C75, IVS-A75, and MC-C75) were in the Advanced Population T r i a l . Ten elite restorers were contributed to the parental trial. H y b r i d ICH-154 gave higher yield (1993 kg/ha) than the mean yield of the Initial H y b r i d T r i a l (1950 kg/ha at 28 locations) and was promoted for advanced testing in 1979. A l l experimental varieties and synthetics did well in their respective trials. SSC-H76 and I C M S 7703 ranked first and second among the test entries in the Initial Population T r i a l , w i t h yields of 1952 kg/ha and 1932 kg/ha, respectively, compared w i t h the trial mean of 1744 kg/ha over 21 locations. Experimental varieties W C C75 (2073 kg/ha) and IVS-A75 (2008 kg/ha) were the top-yielding varieties in the Advanced Population T r i a l (trial mean over 33 locations was 1945 kg/ha). A m o n g the varieties that have been tested for 3 years, WC-C75 ranked first
61
with a mean yield of 1731 kg/ha, which was 94% of the commercial hybrid BJ-104 (Table 6). This variety was recommended for minikit trials in 1979, and was included as a check entry in the A I C M I P Initial and Advanced Population Trials.
Distribution of Seed Material During 1978-79, more than 2700 seed items of breeding and source material including inbreds, restorers, hybrids, synthetics, population progenies, experimental varieties, and disease resistance sources were distributed to breeders in 21 countries.
Biochemistry Protein and Lysine Study During 1978, protein content was estimated on grain samples of 21 entries of I P M A T - 4
grown at four locations. Results indicated a weak relationship between yield and protein content, and between protein content and seed size, confirming results obtained in the previous years. Data for protein content at several locations again showed relatively less variation among locations as compared to variation in yield (Table 7). Data gathered f r o m analysis of various trials conducted at several locations over the past 3 years indicated the following: 1. In pearl millet, the relationship between (a) grain yield and protein content is weak and mostly negative, (b) grain yield and D B C / g protein (reflecting the basic amino acids content) is weak and mostly negative, (c) grain weight and protein content is weak and can be either negative or positive, (d) grain weight and D B C / g protein is weak and mostly negative, and (e) protein content and D B C / g protein is strong and negative. 2. The genotype-environment interaction for protein content is not significant, indicating that breeding for improved protein con-
Table 6. Performance of selected pearl millet populations in the AICMIP trials. Downy mildew {%)
Grain yield (kg/ha) a
BJ-104 Population
1976
1977
1978
Mean
(%)
1976
1977
1978
Mean
WC-C75 DC-3 PSB-8 PSB-3
1490 1490 1530 1330
1631 1579 1532 1574
2073 1986 1795 1898
1731 1685 1619 1601
93.6 91.1 87.6 86.6
0.2 1.5 5.3 2.0
2.2 4.9 4.5 8.9
2.8 3.4 6.6 12.2
1.7 3.3 5.5 7.7
New Vijay Local BJ-104 HB-7
1510 1135
83.1 78.5 100.0 93.8
10.8
1916 1971 2084
1535 1451 1849 1735
4.2
1640
1560 1302 1727 1482
1.8 2.0
8.3 6.7
9.8 5.8
6.6 4.8
1330
1540
1945
1605
41.6*
93.5'
67.9b
67.7b
Trial Mean
7.5
Source: The coordinators review, AICMIP workshop 1979. a. Commercial hybrid check. b. HB-3, a susceptible hybrid check.
63
Table 7. Grain yield (kg/ha) and protein content (%) of IPMAT-4 (1978) entries at four locations. Protein content
Grain yield 1
2
3
4
1
2
3
4
ICH-105 ICH-118 ICH-154 ICH-165 GHB-27
2097 2826 2701 2204 2742
2249 1518 2043 1633 1420
2355 2607 2120 2871 2706
2943 3330 3650 2762 2896
9.8 10.9 10.2 10.0 12.0
11.0 11.2 11.2 11.7 12.0
11.9 12.5 12.3 12.3 12.7
9.5 10.7 10.1 9.3 10.8
MBH-110 PHB-47 BJ-104 NHB-3 SSC-H76
2402 2282 3046 1417 2313
2171 1422 1440 1607 1753
2119 2164 1826 1461 1767
3361 2649 2626 2554 3086
11.5 10.9 10.5 10.6 9.0
10.6 11.7 13.2 11.7 10.5
13.5 12.1 12.2 11.9 11.6
10.8 10.4 1.9 10.0 9.2
WCB-76 MCP-76 RF-A76 IVS-A75 WC-C75
2251 3060 1865 2644 2809
1730 1417 1481 1924 1670
2418 2091 2575 1703 2026
3051 2810 2963 2604 2462
10.3 10.4 9.5 10.6 11.0
10.4 10.3 11.4 10.9 10.5
12.5 12.4 12.5 10.8 11.4
10.3 10.3 10.7 9.0 9.5
MC-C75 ICMS-7703 DC-3 SSC(C1) Bulk Ex Bornu Bulk Local check
2345 2506 2531 2272 1893 2874
1583 1608 1738 1684 1020 1567
2323 1689 1989 1761 2041 2610
3345 3043 3032 2484 2675 2748
9.6 10.2 10.2 10.1 8.8 9.7
11.1 10.4 12.1 11.3 10.0 11.1
11.8 10.6 12.4 11.5 12.3 11.7
9.6 9.6 10.3 10.8 9.3 10.1
2432 17.9 721 1417 3060
1651 34.2 933 1020 2249
2153 25.4 906 1461 2871
2908 18.6 893 2464 3650
10.3 9.8 1.7 8.8 12.0
11.2 8.1 1.5 10.0 13.2
12.1 5.6 1.1 10.6 13.5
10.0 8.5 1.4 1.9 10.8
Entry
Mean CV (%) LSD (0.05) Range: Minimum Maximum
1. ICRISAT (high fertility), 2. ICRISAT (low fertility). 3. Hissar, 4. Bhavanisagar.
tent could be carried out using single location results. 3. Protein contents of the same material grown at different locations do not differ much, although grain yields vary substantially. Thus selection for increased protein content in pearl millet should be possible without detrimental effect to yield or seed size. Breeding
64
work is now under way on a limited scale to examine the possibility of improving both yield and protein content together, using both the conventional approach and recurrent selection. W o r l d Composite was chosen for the recurrent selection approach since it has the highest level and good range of protein content among the current composites in the program. Selection w i l l be effected on yield, protein content, and
other agronomic characters simultaneously. Progenies f r o m crosses involving two of the high protein lines (identified in 1976) with elite breeding lines are now in the F 3 stage. A d d i t i o n al crosses have been made among lines w i t h high protein, low protein, high lysine, and high grain weight to study the inheritance of protein and lysine content and subsequent selection in segregating progenies. During this period 5394 samples of pearl millet were screened for protein, using rapid methods; the range was 5.8 to 16.5 and the mean was 10.6. Sixty-five samples were also screened for lysine, using ion exchange chromatography; the range was 2.1 to 3.8, with a mean of 2.7.
Food Product Study Surveys on consumer preferences in pearl millet were carried out in seven Indian states (Andhra Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan, and T a m i l Nadu) that account for 80% of total area and 73% of pearl millet production in the country. Several food products commonly prepared from pearl millet were identified: breads, porridges, gruels, and boiled, steamed, and fried foods, and snacks. Depending on the product, whole grain, flour, grits, or batter is used as the starting material. Chapati, an unleavened bread made f r o m whole flour, was found to be the most commonly used. Physicochemical studies for chapati characteristics were carried out with 16 pearl millet cultivars, comprising local types and popular Indian hybrids. The ranges and means of various physical and chemical characteristics of these cultivars are indicated in Table 8. In addition to evaluation of several flour qualities, the water absorption, stickiness, and spreading ability of dough were also studied and evaluated subjectively. Chapatis made under standardized conditions were evaluated by a trained taste panel for color, texture, flavor, taste, and acceptability. Chapati quality may be governed by several
Table 8. Physicochemical characteristics of pearl millet flour and chapati quality.a Component
Range
Mean
3.8- 6.0 7.6-10.8 22.6-32.4 63.1-70.5 21.9-27.4 3.6- 7.6 2.0- 2.6 10.8-17.4 1.0- 1.3
5.0 9.2 27.9 66.9 24.6 5.0 2.4 13.7 1.2
Chapati Water for dough (ml/100 g flour) 64.5-77.3 Moisture loss during baking (%) 21.3-32.0 Color and appearanceb 1.6- 3.6 b Texture 1.6- 3.8 1.6- 3.0 Taste* Flavor" 1.8- 3.2 Acceptabilityb 1.2- 3.2
73.5 27.4 2.6 2.8 2.5 2.6 2.5
Flour Swelling capacity v/v v/w Flour solubles (%) Starch (%) Amylose (%) Water soluble amylose (%) Sugars (%) Protein (%) Water-soluble protein (%)
a. Based on 16 cultivars and hybrids. b. Ratings given by ' panelists (4 = excellent, 3 = good, 2 = fair, 1 = poor).
factors of flour, either physical or chemical, that complement each other. Physical factors such as grain density and swelling capacity, and chemical characteristics of flour such as water-soluble protein, nonreducing sugars, amylose, and fiber were found to be related to taste as evaluated by the chapati taste panel. Results of multivariate regression analysis indicated that most of the above factors had some i n fluence on chapati quality (Table 9). Further w o r k is in progress to understand the factors that influence chapati quality.
Sugar Content Study Sugar fractionation of millet flour of eight cultivars was done using Biogel P-2 column. The total sugars content ranged f r o m 2.2 to 2.8%
65
Estimations of stachyose, raffinose, sucrose glucose and fructose were made and their values ranged f r o m 0.06 to 0 . 1 % , 0.7 to 0.8%, 1.3 to 1.8%, and 0.08 to 0.2%, respectively.
Physiology Evaluating Genotypes under Drought Stress Millet is grown mainly under conditions of low and erratic rainfall. Therefore, testing for drought resistance is an essential part of the Pearl M i l l e t Improvement Program. For the past 3 years, selected breeding materials have been screened for resistance during the dry summer season as a joint project of the breeders and physiologists. The method used—described fully in the 1976-77 I C R I S A T Annual Report — involves comparing genotype performance in midseason (panicle initiation to flowering) and terminal (flowering to maturity) stress treatments. Determination of resistance is based
on the performance of the cultivars in the stress treatment relative to that in the nonstressed treatment. Data f r o m 3 years of such testing have been analyzed to determine the factors that influence performance (yield) under stress conditions and to develop appropriate methodology for assessing drought resistance independently of other factors that influence grain yields in the stress treatments. Factors affecting yield in stress treatments. Flowering dates for the genotypes ranged f r o m 38 to 60 days. W i t h the use of single midseason and terminal stress treatments, some genotypes escaped severe stress, and others, stressed at the designated stage, suffered severely. In the midseason stress, the earlier- and later-flowering genotypes yielded less than others (Fig. 1). In the early-flowering genotypes the midseason stress overlapped with flowering, and yields were severely reduced because of spikelet sterility and poor grain set. Lower yields in the later-flowering genotypes may have been related to a general reduction in yields with late flowering in the summer season rather than to specific interaction w i t h the stress treatment.
Table 9. Assessment of chapati qualities as a function of physical and chemical characteristics.a Chapati qualities Characteristic Swelling capacity of flour Amylose Water-soluble amylose Nonreducing sugars Fat Ash Crude fiber
Color 0.19 0.23** - 0.32** 1.69 0.52* - 1.41* 2.13*
Texture
-
-
ND 0.20** ND 2.67 *** 0.35 1.16** 0.95
Taste 0.39*** 0.13* -0.11 ND -0.31* - 1.10** ND
Flavor 0.23*** 0.21*** -0.27** 0.97*** -0.41*** -1.21*** 0.78*
Acceptability 0.46** 0.08 -0.11 ND -0.29 - 1.41*** ND
a. Multivariate regression analysis—chapati qualities as dependent variable tested against physicochemical characteristics as independent variables. ND = No data: variable was not included. *Significant at 0.10. **Signiflcant at 0.01. ***Significant at 0.01.
66
Midseason
related to yields in the nonstress treatment (for the midseason stress, r = 0.58, and for the terminal stress r = 0.44). The individual and the combined contributions of these t w o factors (drought escape and yield potential) to actual grain yield in the stress is presented in Table 10 for the 1978 experiment. It is clear that both of these factors had a substantial effect on grain yields under stress. It is, therefore, necessary to remove these effects while evaluating breeding materials for drought resistance per se.
Terminal stress
1200 1000 800 600
r = 0.46
400 200
r = 0.62
58 Days to flowering Figure 1. Grain yields in the midseason and terminal stress treatments in relation to days to flowering.
In the terminal stress treatment, the earlierflowering genotypes were less affected than the later-flowering ones (Fig. 1), owing to the use of a single general stress that allowed the earlyflowering genotypes to escape. In addition to the effects of time of flowering, yields in both stress treatments were linearly
Method of evaluation. The effects of drought escape and yield potential were removed by use of a regression approach to predict the yields under stress as a function of date of flowering and yield potential. As the flowering date response in midseason stress is a second order polynomial, the equations used under the two stresses were different. These t w o factors accounted for 40 to 60% variation in yield under stress (Table 10). The remaining 40 to 60% constituted drought index (resistance or susceptibility) and experimental error. Standard normal residual, after removing the yield potential and escape factors, was used as an index of drought resistance/susceptibility. Cultivars w i t h values of the residuals falling below the 10% and above 90% quantiles of the normal distribution were considered suscepti-
Table 10. Correlation coefficients between grain yield of pearl millet under drought stress and grain yield of nonstressed cultivars and between gram yield under stress and days to flowering in 1978. Yield in control (YC) Grain yield in midseason stress Grain yield in terminal stress
Days to flowering (bl)
0.58**
-0.04
0.44**
-0.62**
bl + (bl) 2
YC + bl
0.46**
YC + bl + (bl) 2
0.65** 0.74**
** < 0.01
67
ble and resistant, respectively. For many cultivars, the variation in yield under stress was largely explained by these two factors (e.g., BJ-104 and BK 560). There were, however, a few cultivars that did appear to be resistant ( e g . , WC-B76, SSC-C75, and ICH-165) or susceptible (Casady) to one or the other of the stress treatments.
Grain Yield, Grain Number, and Kernel Weight Variation in grain number and kernel weight. G r a i n yield response to variation in grain number and kernel weight was examined in 19 rainy- and postrainy-season crops of A I C M I P hybrid BJ-104 over the past 3 years, and in two rainy season crops of a set of 40 different cultivars grown at I C R I S A T Center in 1978. The mean grain yield of BJ-104 crops was 229 g / m 2 , with a range of 106 to 355 g/m 2 . Variation in grain yield was very strongly related to variation in grain number (r 2 = 0.80; P < 0 . 0 1 ) in the range of 19 000 to 64 000 grains/m 2 (Fig. 2). For the 40 cultivars, mean grain yield was 210 g / m 2 within the 100 to 331 g / m 2 range. Variation in grain yield was again directly related to variation in grain
Crops grown in rainy and postrainy seasons from 1976 to 1978.
360
r 2 =0.80
320 280 240 200 160 120 80 18
26 34 42 50 58 66 Grains per square meter ( x 10-2)
Figure 2. Grain yields in AICMIP hybrid BJ-104 in relation to grain numbers.
68
number (r 2 = 0.54; P 25 μg N/core per day), but only 8 of the 79 lines tested in the irrigated summer season were active. Cultivars of the minor millets Eleusine coracana, Panicum miliaceum, P. miliare, Panicum sp., and Setaria italica showed more consistent activity than pearl millet. Blue green algae were present in mats on the soil surface of many fields. Their extent and nitrogen-fixing activity under pearl millet was generally low, but under tropical grasses, such as Pennisetum purpureum, the mats maybe very active, depending on the wetness of the soil surface and the extent of the plant canopy. Nitrogenase activity of these algal mats ranged
80
f r o m 24 to 119 mg N fixed/m 2 per day, compared with only 0.5 to 1.6 mg N / m 2 per day for surface soil without visible algal growth. N i t r o gen fixation of this order contributes significantly to the soil-nitrogen balance. Activity declined rapidly as the soil surface dried out. Thirty-four nitrogen-fixing bacterial cultures, isolated f r o m pearl millet roots, were identified. Thirteen isolates were f r o m the Spirillaceae, 13 f r o m the Enterobacteriaceae, 5 f r o m the Azotobacteriaceae, and 3 from the Bacillaceae. Of the 10 different media tested for suitability for counting nitrogen-fixing bacteria f r o m soils, a sucrose medium with 100 μg extract added per liter gave the highest counts. The nitrogenase activity associated w i t h pearl millet seedlings grown in vermiculite in 25 x 200 mm test tubes varies with the culture of organisms used. At 14 days after sowing, a maximum activity of 21 μmoles C 2 H 4 / p l a n t per day was obtained with a culture of Derxia sp. The variability among plants in this system was much less than for field-grown plants. It may be possible to screen pearl millet lines more reliably for differences in their ability to stimulate nitrogenase activity in such a system. The pearl millet hybrid BJ-104, grown in washed vermiculite w i t h nitrogen-free nutrient
solution and inoculated with nitrogen-fixing bacteria, gained 34 mg N/plant in 48 days, and for each pot of five plants there was a nitrogen gain of 211 mg. At harvest, nitrogenase activity associated w i t h the roots was 79 μmoles C 2 H 4 / g root per hour, and no activity was found in the vermiculite without roots.
Looking Ahead Breeding. The program w i l l continue to generate and test new hybrids, 'synthetics, experimental varieties, and breeding lines to identify higher yielding genotypes with stable performance and disease resistance to supply to national programs. M o r e of the germplasm accessions and promising breeding material from the West African Cooperative Programs will be utilized to maintain a continuous inflow of new variability. N o w that the techniques for screening ergot and smut resistances have been standardized and the resistance sources have been identified, more emphasis will be placed on incorporation of ergot and smut resistances into high-yielding lines. W o r k will be intensified to develop new seed parents for producing better hybrids. The possibility of improving yield and protein content simultaneously will also be examined. Biochemistry. Analysis of selected germplasm accessions for protein and lysine content w i l l be carried out. Laboratory analysis to determine relationship between physicochemical characteristics of grains and chapati quality w i l l continue. Attempts w i l l be made to improve our taste panel evaluation procedures. Physiology. The drought resistance project w i l l be expanded into a cooperative project w i t h the breeding subprogram to investigate the feasibility of breeding directly for resistance to drought stress under field conditions in drought screening nurseries managed by the physiology team. A project to investigate the basis of adapta-
tion in millet w i l l be initiated in 1979. This w i l l involve direct measurement of crop growth and environment in three locations in India and reanalysis of selected I P M A T data f r o m past years, utilizing additional site data on soil moisture, heat unit accumulation, daylength, etc. W o r k w i l l continue on the development of genetic materials to test hypotheses on means of increasing yield potential in millet (some of these projects were outlined in the report on grain yield response to grain number and grain weight). In order to properly evaluate such hypotheses, materials f r o m a common genetic background, incorporating the desired characteristics, must be bred or selected. Entomology. To date, activities in Millet E n tomology have been mainly observational to obtain an understanding of the insect problems on this crop. Our future emphasis w i l l be to determine the relative abundance and importance of different pests, identification of insects with a potential for becoming pests, and changes in the relative importance of different insects in relation to varieties, farming systems, and other practices. Observations w i l l be made on the relative susceptibility of germplasm and breeders' elite material to different pests. Sampling techniques will be standardized and biology of insects found to be important studied. If considered necessary, resistance screening w i l l be initiated against the key pests. Preliminary observations w i l l also be made on the extent of losses due to insects, to determine the importance of insect pests on pearl millet. Cooperative links w i l l be developed w i t h entomologists in other countries of the S A T , and close links w i l l be maintained w i t h scientists working i n A l l India Coordinated M i l l e t Improvement Project. Pathology. The large-scale DM screening nursery w i l l continue at I C R I S A T Center and the cooperative international P r e - I P M D M N and I P M D M N programs w i l l continue. Evaluation of the causes of differential reactions among test locations w i l l be intensified
81
through a j o i n t project w i t h the University of Reading (England) and the Overseas Development Administration. New seed dressing formulations of R i d o m i l w i l l be evaluated multilocationally. The ergot resistance breeding materials will be tested at the F 4 and F 5 generations, and plans w i l l be made to utilize the developed resistances. The potential for ergot control through pollen management w i l l be further examined. Smut-resistance screening w i l l be intensifed at Hissar, w i t h evaluation of inoculation methods. The I P M S N program w i l l be continued at a few key smut " h o t spots." The rust screening and testing program w i l l continue
with activities similar to the 1978-79 period. Microbiology. A long-term nitrogen balance study will be conducted in the field, using pearl millet lines that have shown potential for high nitrogen uptake and nitrogen-fixing activity. This will permit the estimation of the amount of nitrogen fixation associated with those lines. The association between nitrogen-fixing bacteria and pearl millet will be examined for specificity and to see whether this varies with location. The nitrogen-fixing activity associated w i t h pearl millet and related tropical grasses will be examined in different environments and soil types.
Publications
Institute-level Publications
Journal Articles
SAFEEULLA,
SHETTY,
K.M.,
SUNDARAM, N.V., and WILLIAMS,
R.J. 1976. Final report on the joint investigations on seed transmission of pearl millet downy mildew. Report submitted to the Indian Council of Agricultural Research. ICRISAT, Hyderabad, India. SAFEEULLA, K.M.,
SUNDARAM, N.V., and WILLIAMS,
R.J. 1976. Progress report on the joint study on the seed transmission of pearl millet downy mildew. Report submitted to the Indian Council of Agricultural Research. ICRISAT, Hyderabad, India. WILLIAMS, R.J. ed. 1975. Proceedings of the Consultants Group Meetings on Downy Mildew and Ergot of Pearl Millet, 1-3 Oct 1975, ICRISAT, Hyderabad, India. WILLIAMS,
R.J.,
FREDERIKSEN,
R.A.,
and
GIRARD,
J.C. 1978. Sorghum and pearl millet disease identification handbook. Information Bulletin No. 2, Hyderabad, India: ICRISAT. 88 pp., 59 color plates. (In three versions—English, French & Spanish).
82
S.V.R., and M A I T I , R.K. 1978. Some observations on the root system of some tropical dicotyledonous weeds. Indian Journal of Weed Science 10(l):4-48.
SKINNER, J.D., DAVIES, J.C, and SESHU REDDY, K.V.
1979. A note on the discovery of the male of Acritochaeta distincta M A L L . (Diptera: Muscidae). Journal of the Bombay Natural History Society 75(1) :240241.
Conference Papers K., and APPA RAO, S. 1977. Germplasm and source material for breeding programs. International Pearl Millet Workshop, 29 Aug2 Sept 1977, ICRISAT, Patancheru. A N A N D KUMAR, K., and ANDREWS, D.J. 1977. International cooperation and pearl millet improvement. International Pearl Millet Workshop, 29 Aug-2 Sept 1977, ICRISAT, Patancheru.
A N A N D KUMAR,
ANDREWS, D.J., BHOLA N A T H , V., and HARE, B.W.
1977. Methods of population improvement in pearl millet and sorghum. Second FAO/SIDA Seminar on Field Food Crops in Africa and the Near East, 18 Sept-5 Oct 1977, Lahore, Pakistan. ANDREWS, D.J., and KASSAM, A.H. 1976. The importance of multiple cropping in increasing world food supplies. In Multiple Cropping Symposium, 24-29 Aug 1975, Knoxville, Tennessee. USA: American Society of Agronomy. DAVIES, J.C., and SESHU REDDY, K.V. 1977. Insect pests of sorghum and pearl millet and assessment of insect numbers and losses. Page 12 in Proceedings, All India Workshop on Assessment of Crop Losses due to Pests and Diseases, 19-30 Sept 1977, Bangalore, India. GUPTA, S.C., and ANDREWS, D.J. 1977. Population improvement in pearl millet at ICRISAT. International Pearl Millet Workshop, 29 Aug-2 Sept 1977, ICRISAT, Hyderabad, India. GUPTA.
S.C..
ANAND
KUMAR,
K.,
and
ANDREWS.
D.J. 1978. Varietal diallel analysis for six characters in pearl millet (Pennisetum americanum [L] K. SCHUM), National Seminar on Genetics of Pennisetum. 27-29 Mar 1978, Ludhiana, India. GUPTA, S.C., and ANDREWS, D.J. 1978. Population improvement in pearl millet. International Conference on Cytogenetics and Crop Improvement, 3-6 Mar 1978, Varanasi, India. HARE, B.W., and ANDREWS, D.J. 1977. The develop-
quality of cereals and pulses: rapid screening met* hods for the evaluation of protein quality. Page 49 in Proceedings 46th Annual Meeting of the Society of Biological Chemists, 22-25 Sept 1977, Madras, India. KASSAM,
A.H.,
DOGGETT,
H.,
and ANDREWS,
D.J.
1975. Cereal physiology in relation to genetic improvement of sorghum and millet at ICRISAT. Cereal Consultants Meeting, 14-18 Apr 1975, ICRISAT, Hyderabad, India. KASSAM, A.H., SEETHARAMA, N., ALAGARSWAMY, G.,
and M A I T I . R.K. 1975. Cereal physiology projects. Cereal Consultants Meeting, 14-18 Apr 1975, ICRISAT, Hyderabad, India. KRAMER, F., and WILLIAMS, R J . 1979. Scientist-to-
scientist communication in the context of international agricultural development. Conference on the Communications Responsibilities of the International Agricultural Research Centers, 14-19 May 1979, University of the Philippines, Los Banos, Philippines. REDDY, L.J., GREEN, J.M., SINGH U., BISEN, S.S., and
Jambunathan, R. 1979. Seed protein studies on Cajanus cajan, Atylosia spp, and some hybrid derivatives. Pages 105-117, in vol 2, Proceedings, Symposium on Seed Protein Improvement in Cereals and Grain Legumes, IAEA, FAO, and GSF, 4-8 Sept 1978, Neuherberg, Federal Republic of Germany. Available from the International Atomic Energy Agency, Vienna, Austria.
ment and use of high-yielding varieties of pearl millet. Second FAO/SIDA Seminar on Field Food Crops in Africa and the Near East, 18 Sept-5 Oct 1977, Lahore, Pakistan. JAIN, R.P., and HARE, B.W. 1977. The ICRISAT millet variety crosses and synthetics project. International Pearl Millet Workshop, 29 Aug-2 Sept 1977, ICRISAT, Hyderabad, India.
SESHU REDDY, K.V., and DAVIES, J.C. 1978. The role
JAIN,
The ICRISAT pearl millet hybrid project. International Millet Workshop, 29 Aug-2 Sept 1977, ICRISAT, Hyderabad, India. JAMBUNATHAN, R. 1977. Evaluation of nutritional quality of cereals-screening methodology. Pages 186-199 in Proceedings, Symposium on Genetics Applied to Human Needs. Government of India, Department of Atomic Energy, 10-11 Jan 1977, Bombay, India. JAMBUNATHAN, R. 1978. Improvement of the nutritional quality of sorghum and pearl millet. Eleventh International Congress of Nutrition, 27 Aug1 Sept 1978, Rio de Janeiro, Brazil.
Progress in the identification of resistance to downy mildew, ergot, smut, and rust in pearl millet. International Pearl Millet Workshop, 29 Aug-2 Sept 1977, ICRISAT, Hyderabad, India. SUBBA Rao, R.V., and Dart, P.J. 1979. Research on N 2 -fixation associated with sorghum and pearl millet at ICRISAT. International Workshop on Associative N2-rixation at CENA, Peracicaba, Brazil. THAKUR, R.P., and WILLIAMS, R J . 1978. The effect of pollination on ergot susceptibility in pearl millet. Abstracts of papers. Third International Congress of Plant Pathology, 16-23 Aug 1978, Munich, Federal Republic of Germany.
JAMBUNATHAN, R., and SINGH, U. 1977. Nutritional
VON OPPEN,
R.P.,
HARE, B.W.. and MAJMUDAR. J.V.
1977.
of the entomology program with reference to the breeding of pest-resistant cultivars of sorghum at ICRISAT. Page 8 in Proceedings, National Symposium on Strategies of Insect Pest Control through Integrated Methods. Indian Agricultural Research Institute (IARI), 16-17 Aug 1978, New Delhi, India. SINGH, S.D., THAKUR, R.P., and WILLIAMS, R J . 1977.
M., and JAMBUNATHAN, R.
1978. Con-
83
sumer preferences for cryptic and evident quality characters of sorghum and millet. In Proceedings, Diamond Jubilee Scientific Session of the National Institute of Nutrition, 23-27 Oct 1978, Hyderabad, India. WILLIAMS, R.J. 1979. Position paper on seed transmission of some graminaceous downy mildews. International Conference on Graminaceous Downy Mildew Disease, 28 Nov-4 Dec 1979, Bellagio, Italy. WILLIAMS, R.J., and KUMAR, J. 1979. Multilocational testing in the ICRISATcrop improvement programs. Workshop on Concepts and Philosophy of International Testing, 14-18 Aug 1979, El Batan, Mexico. WILLIAMS, R.J. and SINGH, S.D. 1978. International
screening for pearl millet downy mildew resistance. Abstracts of papers. Third International Congress of Plant Pathology, 16-23 Aug 1978, Munich, Federal Republic of Germany. Miscellaneous Newsletter; International Working Group on Graminaceous Downy Mildews, 1(1):3; 1(2):3; 1(2):6.
84
Contents Breeding Development of Lines Development of Populations Development of Hybrids Breeding for Disease Resistance Breeding for Insect Resistance Natural Outcrossing Breeding for New Plant Types Research in Australia
Biochemistry Evaluation of Cooking Quality Characteristics Total Sulphur and Sulphur Amino Acids Tryptophan Biochemical Changes During Maturation
Physiology Growth Analysis Determinate vs. indeterminate cultivars Cultural Practices in Pigeonpea Response to plant population Response with thinning for forage harvest Effect of foliar nutrient sprays
Entomology Survey of Insect Pests Host-Plant Resistance Biological and Ecological Studies Insect Damage to Nodules Pest Management Studies
87 87 87 88 89 90 90 91 92 93 93 94 94 94 95 95 95 95 95 96 96 98 98 100 101 102 102
Pathology Wilt Development of sick plots/sick pots Developing "sand culture" technique for screening Screening for resistance Sterility Mosaic Studies on the mite vector Screening for resistance Phytophthora Blight Identification of the fungus Media for growth Optimum temperature for storing the fungus cultures Fungicidal seed dressing to control blight Screening for resistance Surveys Interaction between Sterility Mosaic and Powdery Mildew Multiple Disease Resistance
Microbiology Soil Populations of Rhizobia Rhizobium Growth Characteristics Pigeonpea Response to Seed Inoculation Screening Pigeonpea for Symbiotic Characteristics Growth of Pigeonpea in Pot Culture
103 103 103 103 103 103 104 104 104 104 104 104 104 105 105 105 105 105 105 106 106 107 107
Looking Ahead
108
Publications
110
PIGEONPEA
Breeding
Development of Lines
At I C R I S A T Center, breeding for improvement of medium maturity (160-170 days) genotypes of pigeonpeas receives major emphasis. These are usually grown as intercrops, with low inputs. The major breeding objectives for increasing yields in such production systems are the incorporation into promising genotypes of disease resistance, lower levels of susceptibility to pod borers, and increased genetic potential for yield.
Last year we reported encouraging results with inbred lines derived f r o m existing cultivars. Lines of T - 2 1 , entered in the 1978 A l l India Coordinated Trials, had comparatively high yields at Badnapur, Junagadh, Rahuri, and Varanasi, giving an indication of satisfactory adaptation of inbred lines.
Breeding for improved late-maturing genotypes adapted to traditional production systems typified by northern India is in progress at Gwalior, India. The objectives are the same as above. The development of genotypes suitable for nontraditional systems largely involves shortseason cultivars. For these, our core program is located at Hissar in northern India, and contract research is in progress at the U n i versity of Queensland in Australia. In addition to disease resistance and high yield, emphasis has been on photoperiod insensitivity and on improving consumer acceptability (chiefly seed size and color). In our role of providing breeding material for selection for local adaptation, we must continually reevaluate our objectives and the environments under which we select. For example, the traditional material is grown as a sole crop as well as an intercrop, and if hybrids should become available, sole cropping might increase substantially. There is an increasing interest i n , and research effort o n , the planting of pigeonpeas as a dry-season crop. To date there has been no breeding effort in this environment. Production of pigeonpeas as a sole crop under irrigation in dry areas is expanding.
Our tests indicated superior yield performance of several new lines, and eight of medium maturity (two resistant to sterility mosaic) were submitted to the Indian program for testing. Ten early-maturing lines were submitted to the A l l India Coordinated Trials. T w o international trials of vegetable-type lines (for green pea harvest) were conducted, one of 26 early-maturing lines and the other of seven medium-maturing experimental lines. Results were received f r o m 6 of 15 locations. Some experimental lines were superior to the local checks (in Puerto Rico and Kenya). Observation nurseries of early- and mediummaturity new lines were furnished to national program breeders. On the basis of cooperators' reports, 17 of the medium-maturity lines were advanced to replicated multilocation tests.
Development of Populations We are advancing some populations using mass selection for yield, and several others (composite populations involving male sterility, dual populations, and single-cross advanced generation bulks) without selection. Mass selection appears to be ineffective f o r increasing yield, so far. The mean performance and variance of some of the other populations w i l l be determined by deriving lines and testing
87
them in the S 2 generation. Currently t w o F 4 populations, advanced by single-pod descent, are being evaluated for variance of the populat i o n and heterozygosity of F 5 lines. The mean performance of 38 such F 4 bulks are to be tested in multilocation trials. Local breeders can then derive lines f r o m the highest-yielding bulks, screen the progenies in F 6 ; and conduct yield trials in F 7 , thus having material advanced enough to increase for release after only 3 years.
Development of Hybrids The genetic male-sterile lines in hand are f r o m two germplasm lines, one f r o m A n d h r a Pradesh (MS-3A) and the other f r o m Maharashtra ( M S - 4 A ) . They are of medium-late maturity, susceptible to the major diseases, and non-
2100
X MS-3A
Pollen parent
uniform. Inbred lines are being produced f r o m them. Backcrossing is also being done to transfer male sterility to good lines of different maturity and to transfer disease resistance to the sterile lines. We are also actively searching for cytoplasmic sterility and are studying the nature of apparent cytoplasmic sterility in intergeneric derivatives with Atylosia scarabaeoides cytoplasm. We have now completed 2 years of tests of F 1 hybrids, f r o m crosses of particular cultivars and breeding lines with the two sterile populations M S - 3 A and MS-4A. Cases of specific combining ability were observed, as would be expected f r o m the results of diallel studies. The highest percentage of heterosis was generally found in hybrids w i t h low-yielding pollen parents, and a generally lower percentage heterosis was found in those with higheryielding pollen parents (Fig. 1). The maximum
X MS-4A
1900 1700
C-11 y i e l d
1500 1300 1100 000 700 600 300 100 0 Puss Ageti
7176
4234
TTB-7
T-7
8604
PS-41
LRG-30
3193 -12
7065
BDN-1
Figure 1. Grain yields of pollen parents and their hybrids with MS-3A and MS-4A intercropped with eowpeas at ICRISAT Center in 1978 compared with high-yielding cultivar C-11 (yield of Pusa Ageti from second flush only).
88
A wilt-resistant line of pigeonpea stands in contrast to a susceptible line at ICRISAT Center.
yield advantage of a hybrid compared with the highest-yielding cultivar was 31.5% in the first year's test and 17% in the second. Two hybrids, MS-4A x C-11 and MS-4A x B D N - 1 , were entered in the A l l India Coordinated Trials. We will have seed production blocks of two hybrids, MS-3A x C-11 and MS-4A x B D N - 1 , in the coming year, to test the production system developed in smallplot trials. Seed of the male-sterile lines has been distributed to local breeders for hybridization with locally adapted cultivars, and more new hybrids will be included in preliminary tests at I C R I S A T Center.
Breeding for Disease Resistance Several breeding lines possessing resistance
to sterility mosaic have been selected. Tests of 15 resistant lines were furnished to six locations in 1978-79. Observations were obtained from only two locations, and yield differences were nonsignificant. Genetic studies indicate that four allelic genes are involved in the control of resistance and susceptibility to sterility mosaic. In the material tested, there apparently were two alleles for immunity, one for tolerance (ring-spot symptom), and one for susceptibility. Susceptibility was dominant to all of the resistance genes. Progress in breeding new lines with wilt resistance has been slow, even with excellent sources of resistance available from the pathologists. The inheritance of wilt resistance appears to be complex. In 1979-80, we will be screening for seed yield among single-plant
89
progenies derived f r o m 36 progenies that have survived 3 or more years of screening in the wilt nursery. Selections resistant to Phytophthora blight were made in the F 3 and F 4 generations, and their progenies w i l l be screened in the blight nursery. We now screen lines for resistance to sterility mosaic, w i l t , and Phytophthora blight, in a multiple disease nursery. Of the 886 progenies tested, 20 showed promise; 121 single-plant progenies f r o m these w i l l be retested. Some lines f r o m the other disease nurseries w i l l also be tested.
Breeding for Insect Resistance Screening f o r reduced susceptibility to pod borers in pigeonpeas is carried out in the entomology section. A collaborative project on transfer of resistance (or perhaps reduced susceptibility) f r o m particular Atylosia species is under way. Promising plants in F 2 populations of intergeneric crosses were intermated. Plants selected in the intermated F 1 s w i l l be tested as progenies, and the best ones will be intermated again. This w o r k is relatively long term, and it is likely to take many generations to derive pigeonpea lines having sufficient desirable characteristics to be acceptable.
Natural Outcrossing The floral biology of the pigeonpea favors 100% self-pollination, but in fact there is usually some hybrid seed produced on u n protected plants as a result of bee visits to the flowers. O u r earlier observations revealed that several species of w i l d bees visit the flowers and that species of Megachyle are the most important pollinators. We take advantage of the bee pollination in the production of hybrid seed on male-sterile plants and in population improvement breeding schemes, but natural crossing poses problems in developing pure lines and in maintaining p u r i t y of seed of released cultivars.
90
We continue to study several aspects of this phenomenon to better capitalize on it and more effectively control it. We have observed pod-set on male-sterile plants and normal fertile plants grown in a mixed population at I C R I S A T Center. The average number of pods per plant and the distribution of numbers of pods per plant were almost the same in both types (Fig. 2). This indicates an equal opportunity for pollination in both kinds of flowers, even though the male-steriles were entirely dependent on the pollen deposited by visiting bees. To determine the applicability of results f r o m I C R I S A T Center to other areas, a standard field layout of green-stem and purplestem plants was planned for 12 locations in India this year. At I C R I S A T Center, under insecticide-sprayed conditions, the average percentage of hybrid seeds produced on the green plants was 21 (Fig. 3). At Varanasi, the only
Male sterile Normal
5
4
3
2
1
0 300
400 500 600 Class centers: pods/plant
700
Figure 2. Frequencies of numbers of pods per plant on male sterile and normal plants under open pollination at ICRISAT Center.
ICRISAT Center BHU, Varanasi
40
parents in the open, we recorded an increased percentage of crosses set and a lower incidence of pod borer damage.
35
Breeding for New Plant Types 30 The extension of pigeonpea to new systems of production might be possible through the development of new plant types. Specific objectives toward this end exist in the breeding p r o g r a m ; for example, development of vigorous, spreading, many-branched plants for intercropping with cereals. We are also attempting to combine high yield with unusual plant types, and then to evaluate the usefulness of such types.
25 20 15 10 5 0 5
10 15 20 25 30 35 40 Class centers: outcrossed seed (%)
Figure 3. Frequencies of plants with different percentages of outcrossing in tests at ICRISAT Center and at BHU, Varanasi. other location for which data are available, the mean outcrossing was 27%. Figure 3 shows that crossing by bees on normal fertile flowers was not constant f r o m plant to plant; the range was f r o m 7 to 38% at I C R I S A T Center and 10 to 4 1 % at Varanasi. These results suggest that possibilities of exploiting natural crossing, and coping with the problems caused by it would be similar at the two locations. Continued research is needed on this problem, particularly at other locations and in different seasons. We are also investigating different ratios of sterile females to pollinator rows for hybrid seed production and effects of distance and barriers on intercrossing between fields. To avoid random crosses by bees on handpollinated flowers, the parent lines were enclosed in a mesh-covered cage. To reduce plant size, planting was delayed until September. Compared with crossing July-sown
D w a r f plants have several advantages, including easier application of insecticide, partitioning of more photosynthate to pods in the absence of large, woody main stems, and better suitability to mechanical harvest. Figure 4 illustrates the five genetic dwarfs that are used as parents. D 1 to D 3 appeared in the F 2 population f r o m two normal parents. The simplest hypothesis was that two recessive genes controlled dwarfness and that each normal parent carried one. In crosses w i t h five parents, monogenic inheritance was observed, indicating that the normal parents carried one gene for dwarfness in the recessive condition. Of the hundreds of crosses made to date, only one has produced these dwarf plants. This observat i o n , together w i t h the evidence that five random parents carry one dwarf gene each, suggests that the frequency of the second dwarf gene must be extremely low. D w a r f selections f r o m hybrids are being advanced and evaluated as progeny rows. Figure 4 also shows that one of the lines, ICP-7952, branched very profusely. Three such lines were selected in recent germplasm collections. Since the number of secondary branches is usually positively correlated w i t h the grain yield, these lines are of interest. Conversely, a single-culm nonbranching plant type is also being used in crosses to produce nonbranching lines of different matur-
91
Figure 4. Five genetie dwarf plant types (D0 to D4), and ICP-7952, characterized by high branch number.
ities; these may give a yield advantage when sown at closer spacings.
Research in Australia A significant portion of northern Australia consists of semi-arid tropics. Because the requirements of this area could not be met at I C R I SAT Center's research farm, cooperative re-
92
search with the University of Queensland, Australia, was formalized in 1977. The primary objective has been the development of short-season pigeonpea genotypes and production systems suitable for mechanical harvesting in extensive dryland agriculture. Agronomic and breeding studies of photoperiod-insensitive material continued in 1979. We now know that this material is capable of high seed yields, with some lines producing up to 4500 kg/ha from the
plant crop and 6500 kg/ha total f r o m the plant and first ratoon crops in experimental plots. Lines differ in time to flowering and maturity, and we have selected those that appear to be quite synchronous in flowering and podding. These lines will be evaluated in regional trials in Australia and have been supplied to a number of cooperators internationally. A photoperiod-sensitive cultivar, Royes, has been released in Australia, and commercial production is expected in 1979-80. The adaptation of this cultivar is limited by the incidence of frost, and earlier-maturing Royes-type breeding lines have been developed and introduced. They will be evaluated regionally in 1979-80. An active program of plant introduction is continuing, particularly f r o m I C R I S A T Center. D u r i n g 1979, hybridization has been carried on w i t h photoperiod-insensitive material for three main objectives: to transfer desirable seed and pod characters into the insensitive genetic background, to study the inheritance of insensitivity, and to commence quantitative breeding analyses of short-duration pigeonpea populations. In addition, we are conducting growth analysis and light interception studies of insensitive canopies to guide our agronomic research. G r o w t h cabinets are being used to study the effects of photoperiod-temperature
interaction on floral development, and studies on germination of immature seed have commenced. The last t w o programs are directed, in part, towards accomplishing rapid generation turnover in this crop.
Biochemistry D u r i n g 1978-79, in addition to routine screening of samples, studies were carried out on the cooking quality of dhal (dried split seeds), determination of amino acids, and biochemical changes in seeds during maturation.
Evaluation of Cooking Quality Characteristics D h a l samples of 25 cultivars were evaluated for their cooking time, and were analyzed for various physicochemical characteristics (Table 1). Variation (24-68 min) in the cooking time of these cultivars was large in comparison w i t h that of 20 market dhal samples, which ranged between 22 and 28 m i n . A negative and highly significant correlation (r = - 0 . 8 1 , P < 1%) was observed between the cooking time and the
Table 1. Physicochemical characteristics of dhal samples of pigeonpea.a Component
Range
Mean
Cooking time (min) Solids dispersed (%) Water absorption (w/w) (a) Soaking at room temp, for 24 hr (b) Heating at 80°C for 1 hr (c) Boiling at 100°C for 25 min
25 -68 20.80-54.7 0.61- 1.08 1.21- 2.06 1.69- 2.65
0.88 1.54 2.25
Increase in volume (v/v) during boiling at 100°C for 25 min Gelatinization temperature of isolated starch (°C) Water soluble amylose (%) Starch content (%)
1.18- 1.86 73 -81 7.3 -12.0 51.5 -63.4
1.51 76 9.8 58.6
38 37.9
a. n = 25.
93
amount of solids dispersed during the cooking process. The quantity of water absorbed (w/w) by dhal samples when heated at 100°C f o r 25 m i n was negatively and significantly correlated (r = - 0.81, P
